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Understanding Quadrilaterals And Practical Geometry

Class 8th Mathematics NCERT Exemplar Solution
Exercise
  1. If three angles of a quadrilateral are each equal to 75°, the fourth angle isA.…
  2. For which of the following, diagonals bisect each other?A. square B. kite C.…
  3. For which of the following figures, all angles are equal?A. rectangle B. kite C.…
  4. For which of the following figures, diagonals are perpendicular to each other?A.…
  5. For which of the following figures, diagonals are equal?A. trapezium B. rhombus C.…
  6. Which of the following figures satisfy the following properties? - All sides are…
  7. - Has two pairs of congruent adjacent sides. Which of the following figures…
  8. - Only one pair of sides are parallel. Which of the following figures satisfy the…
  9. Which of the following figures do not satisfy any of the following properties? -…
  10. Which of the following properties describe a trapezium? (A) A pair of opposite…
  11. Which of the following is a property of a parallelogram?A. Opposite sides are…
  12. Which is the maximum number of obtuse angle that a quadrilateral can have?A. 1 B.…
  13. How many non-overlapping triangles can we make in a n-gon (polygon having n…
  14. What is the sum of the angles of a pentagon?A. 180° B. 360° C. 540° (d)720°…
  15. What is the sum of the angles of a hexagon?A. 180° B. 360° C. 540° (d)720°…
  16. If two adjacent angles of a parallelogram are (5x-5)° and (10x + 35)°, then the…
  17. A quadrilateral whose all sides are equal, opposite angles are equal and the…
  18. A quadrilateral whose opposite sides and all angles are equal is aA. rectangle B.…
  19. A quadrilateral whose all sides, diagonals and angles are equal is aA. square B.…
  20. How many diagonals does a hexagon have?A. 9 B. 8 C. 2 D. 6
  21. If the adjacent sides of the parallelogram are equal then parallelogram is aA.…
  22. If the diagonals of the quadrilateral are equal and bisect each other, then the…
  23. The sum of all exterior angles of a triangle isA. 180° B. 360° C. 540° (d)720°…
  24. Which of the following is an equiangular and equilateral polygon?A. square B.…
  25. Which one has all the properties of a kite and a parallelogram?A. trapezium B.…
  26. The angles of the quadrilaterals are in the ratio 1:2:3:4, the smallest angle…
  27. In the trapezium ABCD, the measure of ∠D is A. 55° B. 115° C. 135° D. 125°…
  28. A quadrilateral has three acute angles. If each measures 80°, the measure of the…
  29. The number of sides of a regular polygon where each exterior angle has a measure…
  30. In a parallelogram PQRS, if ∠p= 60°, then other three angles areA. 45°, 135°,…
  31. If two angles of the parallelogram are in the ratio 2:3, then the measure of…
  32. If PQRS is a parallelogram, then e^there there eξ sts P - e^there there eξ sts R…
  33. The sum of the adjacent angles of a parallelogram isA. 180° B. 120° C. 360° D.…
  34. The angle between the two altitudes of a parallelogram through the same vertex of…
  35. In the given figure, ABCD and BCDE are parallelograms with common base DC. If BC…
  36. Length of one of the diagonals of a rectangle whose sides are 10 cm and 24 cm…
  37. If the adjacent angles of a parallelogram are equal, then the parallelogram is…
  38. Which of the following can be four interior angles of a quadrilateral?A. 140°,…
  39. The sum of angles of a concave quadrilateral isA. more than 360° B. less than…
  40. Which of the following can never be the measure of exterior angle of a regular…
  41. In the figure, BEST is a rhombus. Then the value of y-x is A. 40° B. 50° C. 20°…
  42. The closed curve which a polygon is also isA. z B. x C. square D. infinity…
  43. Which of the following is not true for an exterior angle of a regular polygon…
  44. PQRS is a square. PR and SQ intersect at O. Then l POQ is aA. right angle B.…
  45. Two adjacent angles of a parallelogram are in the ratio 1:5. Then all the angles…
  46. A parallelogram PQRS is constructed with sides QR = 6cm. PQ = 4cm and 2 PQR =…
  47. The angles P, Q, R and S of a quadrilateral are in the ratio 1:3:7:9. Then PQRS…
  48. PQRS is a trapezium in which PQ 1 SR and l P = 130°, angle Q = 110°, then angle R…
  49. The number of sides of a regular polygon who’s each interior angle is of 135°…
  50. If a diagonal of a quadrilateral bisects both the angles, then it is aA. kite B.…
  51. To construct a unique parallelogram, the minimum number of measurements required…
  52. To construct a unique rectangle, the minimum number of measurements required isA.…
  53. In quadrilateral HOPE, the pairs of opposite sides are____ Fill in the blanks to…
  54. In quadrilateral ROPE, the pairs of adjacent angles are______ Fill in the blanks…
  55. In quadrilateral WXYZ, the pairs of opposite angles are___ Fill in the blanks to…
  56. The diagonals of the quadrilateral DEFG are ______ and _______. Fill in the…
  57. The sum of all _______ of a quadrilateral is 360°. Fill in the blanks to make the…
  58. The measure of each exterior angle of a regular pentagon is ________. Fill in the…
  59. Sum of the angles of a hexagon is _______. Fill in the blanks to make the…
  60. The measure of each exterior angle of a regular polygon of 18 sides is ________.…
  61. The number of sides of regular polygon, where each exterior angle has a measure…
  62. sum is a closed curve entirely made up of the line segments. The another name for…
  63. A quadrilateral that is not a parallelogram but has exactly two opposite angles…
  64. The measure of each angle of regular pentagon is _________. Fill in the blanks to…
  65. The name of three-sided regular polygon is _______. Fill in the blanks to make…
  66. The number of diagonals in a hexagon is ______. Fill in the blanks to make the…
  67. A polygon is a simplest closed curve made up of only ________. Fill in the blanks…
  68. A regular polygon is a polygon whose all sides are equal and all _____ are equal.…
  69. The sum of interior angles of a polygon of n sides is ______ right angles. Fill…
  70. The sum of all exterior angles of a polygon is _______. Fill in the blanks to…
  71. _______ is a regular quadrilateral. Fill in the blanks to make the statements…
  72. A quadrilateral in which a pair of opposite sides is parallel is _____. Fill in…
  73. If all sides of a quadrilateral are equal, it is a ________. Fill in the blanks…
  74. In a rhombus diagonal intersect at _______ angles. Fill in the blanks to make the…
  75. _______ measurements can determine a quadrilateral uniquely. Fill in the blanks…
  76. A quadrilateral can be constructed uniquely if its three sides and ______ angles…
  77. A rhombus is a parallelogram in which _______ sides are equal. Fill in the blanks…
  78. The measure of ____ angle of concave quadrilateral is more than 180°. Fill in the…
  79. A diagonal of a quadrilateral is a line segment that joins two _______ vertices…
  80. The number of sides in a regular polygon having measure of an exterior angle as…
  81. If the diagonals of a quadrilateral bisect each other, it is a ________. Fill in…
  82. The adjacent sides of a parallelogram are 5cm and 9cm. It's perimeter is…
  83. A nonagon has _______ sides. Fill in the blanks to make the statements true.…
  84. Diagonals of a rectangle are _________. Fill in the blanks to make the statements…
  85. A polygon having 10 sides known as _________. Fill in the blanks to make the…
  86. A rectangle whose adjacent sides are equal becomes a ________. Fill in the blanks…
  87. If one diagonal of a rectangle is 6cm long, length of the other diagonal is…
  88. Adjacent angles of a parallelogram are _____. Fill in the blanks to make the…
  89. If only one diagonal of a quadrilateral bisects the other, then the quadrilateral…
  90. The trapezium ABCD with AB | CD, if ∠A = 100^0 , then ∠D = Fill in the blanks to…
  91. Fill in the blanks to make the statements true. The polygon in which sum of all…
  92. All angles of trapezium are equal. State whether the statements are true (T) or…
  93. All squares are rectangles. State whether the statements are true (T) or false…
  94. All kites are squares. State whether the statements are true (T) or false (F).…
  95. All rectangles are parallelograms. State whether the statements are true (T) or…
  96. All rhombuses are squares. State whether the statements are true (T) or false…
  97. Sum of all the angles of a quadrilateral is 180°. State whether the statements…
  98. A quadrilateral has two diagonals. State whether the statements are true (T) or…
  99. Triangle is a polygon whose sum of exterior angles is double the sum of interior…
  100. phi is a polygon. State whether the statements are true (T) or false (F).…
  101. A kite is not a convex quadrilateral. State whether the statements are true (T)…
  102. The sum of interior angles and the sum of extreme angles taken in an order are…
  103. If the sum of interior angles is double the sum of exterior angles taken in an…
  104. A polygon is regular if all of its sides are equal. State whether the statements…
  105. Rectangle is a regular quadrilateral. State whether the statements are true (T)…
  106. If diagonals of a quadrilateral are equal, it must be a rectangle. State whether…
  107. If opposite angles of a quadrilateral are equal, it must be parallelogram. State…
  108. The interior angles of the triangle are in the ratio 1:2:3, then the ratio of…
  109. sum is a concave pentagon. State whether the statements are true (T) or false…
  110. Diagonals of a rhombus are equal and perpendicular to each other. State whether…
  111. Diagonals of a rectangle are equal. State whether the statements are true (T) or…
  112. Diagonals of a rectangle bisect each other at right angles. State whether the…
  113. Every kite is a parallelogram. State whether the statements are true (T) or…
  114. Every trapezium is a parallelogram. State whether the statements are true (T) or…
  115. Every parallelogram is a rectangle. State whether the statements are true (T) or…
  116. Every trapezium is a rectangle. State whether the statements are true (T) or…
  117. Every rectangle is a trapezium. State whether the statements are true (T) or…
  118. Every square is a rhombus. State whether the statements are true (T) or false…
  119. Every square is a parallelogram. State whether the statements are true (T) or…
  120. Every square is a trapezium. State whether the statements are true (T) or false…
  121. Every rhombus is a trapezium. State whether the statements are true (T) or false…
  122. A quadrilateral can be drawn if only measure of four sides are given. State…
  123. A quadrilateral can have all four angles as obtuse. State whether the statements…
  124. A quadrilateral can be drawn if all the four sides and one diagonal is given.…
  125. A quadrilateral can be drawn when all the four angles and one side is given.…
  126. A quadrilateral can be drawn if all four sides and one angle is known. State…
  127. A quadrilateral can be drawn if three sides and two diagonal diagonals are…
  128. If diagonals of a quadrilateral bisect each other. it must be a parallelogram.…
  129. A quadrilateral can be constructed uniquely if three angles and any two sides…
  130. A parallelogram can be constructed uniquely if both diagonals and the angle…
  131. A rhombus can be constructed uniquely if both diagonals are given. State whether…
  132. The diagonal of a rhombus is 8cm and 15 cm. Find its side.
  133. Two adjacent angles of a parallelogram are in the ratio 1:3. Find its angles.…
  134. Of the four quadrilaterals- square, rectangle, rhombus and trapezium- one is…
  135. In a rectangle ABCD. AB = 25cm and BC = 15cm. In what ration does the bisector…
  136. PQRS is a rectangle. The perpendicular ST from theta S on PR divides theta S in…
  137. A photo frame is in the shape of quadrilateral. With one diagonal longer than…
  138. The adjacent angles of a parallelogram are (2x -4)° and (3x - 1) °. Find the…
  139. The point of intersection of diagonals of a quadrilateral divides one diagonal…
  140. The ration between exterior angle and interior angle of a regular polygon is…
  141. Two sticks each of length 5cm are crossing each other such that they bisect each…
  142. Two sticks each of length 7cm are crossing each other such that they bisect each…
  143. A playground in the town is in the form of a kite. The perimeter is 106 metres.…
  144. In rectangle READ. Find ∠EAR, ∠ RAD and ∠ROD.
  145. In rectangle PAIR. Find ARI,RMI and PMA.
  146. In parallelogram ABCD, find∠ B, ∠C and ∠D.
  147. In parallelogram PQRS. O is the mid-point of SQ. Find ∠S, ∠R. PQ, Qr and…
  148. In rhombus BEAM. Find theta AME and theta AEM.
  149. In parallelogram FIST. Find theta SFT, theta OST and theta STO.
  150. In the given parallelogram YOUR, ∠RUO = 120° ad OY is extended to point S such…
  151. In kite WEAR, ∠WEA = 70° and ∠ARW = 80°. Find the remaining two angles.…
  152. A rectangular MORE, is shown below: n Answer the following questions by giving…
  153. In parallelogram LOST, SN Ol and SM LT. Find theta STM, theta SON and theta NSM.…
  154. In trapezium HARE. EP and RP are bisectors of E and R respectively. find ∠HAR…
  155. In parallelogram MODE, the bisector of ∠M and O meet at Q. Find the measure of…
  156. A playground is in the form of a rectangular ATEF, two players are standing at…
  157. In the following figure of a ship. ABDH and CEFG are two parallelograms. Find…
  158. A rangoli has been drawn on a floor of house. ABCD and PQRS both are in the…
  159. ABCDE is a regular pentagon. The bisector of angle A meets the side CD at M.…
  160. Quadrilateral EFGH is a rectangular in which J is the point of intersection of…

Exercise
Question 1.

If three angles of a quadrilateral are each equal to 75°, the fourth angle is
A. 150°

B. 135°

C. 45°

D. 75°


Answer:

Let the fourth angle be x


Since the sum of interior angles of a Quadrilateral is 3600


x + 3×750 = 3600


⇒ x = 3600 – 2250


⇒ x = 1350


Question 2.

For which of the following, diagonals bisect each other?
A. square

B. kite

C. trapezium

D. quadrilateral


Answer:

In a square the diagonals bisect each other because both the opposite side pairs of a square are parallel. But in a trapezium only one pair of opposite pair are parallel. In a kite no opposite pairs are parallel.


Question 3.

For which of the following figures, all angles are equal?
A. rectangle

B. kite

C. trapezium

D. rhombus


Answer:

In a rectangle all the angles are at right angle and hence they are all equal. But in a kite trapezium or rhombus all the angles are not right angles hence not equal.


Question 4.

For which of the following figures, diagonals are perpendicular to each other?
A. parallelogram

B. kite

C. trapezium

D. rectangle


Answer:

In a Kite one pair of opposite angles are at right angles and the adjacent sides are equal. So their diagonals are perpendicular. But in a trapezium, parallelogram or rectangle it doesn’t happen.


Question 5.

For which of the following figures, diagonals are equal?
A. trapezium

B. rhombus

C. parallelogram

D. rectangle


Answer:

In a rectangle since all the four angles are equal hence the diagonals are equal. But in a trapezium, parallelogram or rhombus all the angles are not equal hence their diagonals are unequal.


Question 6.

Which of the following figures satisfy the following properties?

- All sides are congruent.

- All angles are right angles.

- Opposite sides are parallel.
A.

B.

C.

D.

Option:(c)


Answer:

R is a square. In a square all sides are equal, all angles are equal and at right angles and also opposite sides are parallel. P,Q,S are a trapezium, parallelogram and rectangle respectively whose all sides are not equal.


Question 7.

Which of the following figures satisfy the following property?

- Has two pairs of congruent adjacent sides.
A.

B.

C.

D.


Answer:

R is a kite whose adjacent sides are equal. P ,Q & S are a trapezium ,parallelogram and rectangle respectively whose adjacent sides are unequal.


Question 8.

Which of the following figures satisfy the following property?

- Only one pair of sides are parallel.
A.

B.

C.

D.


Answer:

P is a trapezium and has only one pair of parallel side. Q,R,S is a parallelogram ,square and rectangle respectively which has two pair of parallel side.


Question 9.

Which of the following figures do not satisfy any of the following properties?

- All sides are equal.

- All angles are right angles.

- Opposite sides are parallel.
A.

B.

C.

D.


Answer:

Q is a square. In a square all sides are equal, all angles are equal and at right angles and also opposite sides are parallel. P,S,R are a trapezium, parallelogram and rectangle respectively whose all sides are not equal.


Question 10.

Which of the following properties describe a trapezium?

(A) A pair of opposite side is parallel.

(B) The diagonals bisect each other.

(C) The diagonals are perpendicular to each other.

(D) The diagonals are equal.

Option: (A)


Answer:

A trapezium is a quadrilateral which has only one pair of sides which are parallel. The other properties are not true for trapezium.



Question 11.

Which of the following is a property of a parallelogram?
A. Opposite sides are parallel.

B. The diagonals bisect each other at right angles.

C. The diagonals are perpendicular to each other.

D. All angles are equal.


Answer:

In a parallelogram the opposite sides are parallel. The other properties are not true.


Question 12.

Which is the maximum number of obtuse angle that a quadrilateral can have?
A. 1

B. 2

C. 3

D. 4


Answer:

Sum of interior angles of a quadrilateral is 3600. An obtuse angle is an angle between 900 and 1800 .So all the angles can’t be obtuse since then the sum will exceed 3600.So maximum it can have 3 obtuse angle.


Question 13.

How many non-overlapping triangles can we make in a n-gon (polygon having n sides), by joining the vertices?
A. n-1

B. n-2

C. n-3

D. n-4


Answer:

There can be n-1 lines that can be drawn from one vertices. Out of these 2 sides are adjacent sides so n-3 lines can be drawn. When a n-gon is divided by n-3 lines the n-gon is divided into n-2 triangles.


Question 14.

What is the sum of the angles of a pentagon?
A. 180°

B. 360°

C. 540°

(d)720°


Answer:

Sum of interior angles of a polygon = (2n-4)×900 where n represents the number of sides of a polygon

In this problem n = 5


⇒ Sum of interior angles = (10-4) ×900


⇒ Sum of interior angles = 5400


Question 15.

What is the sum of the angles of a hexagon?
A. 180°

B. 360°

C. 540°

(d)720°


Answer:

Sum of interior angles of a polygon = (2n-4)×900 where n represents the number of sides of a polygon

In this problem n = 6


⇒ Sum of interior angles = (12-4) ×900


⇒ Sum of interior angles = 7200


Question 16.

If two adjacent angles of a parallelogram are (5x-5)° and (10x + 35)°, then the ratio of these angles is
A. 1:3

B. 2:3

C. 1:4

D. 1:2


Answer:

Adjacent angles of a parallelogram are supplementary

5x-5 + 10x + 35 = 180


⇒ 15 x + 30 = 180


⇒ 15x = 150


⇒ x = 10


⇒ 5x-5 = 450


⇒ 10x + 35 = 1350


⇒ Ratio = 1:3


Question 17.

A quadrilateral whose all sides are equal, opposite angles are equal and the diagonals bisect each other at right angles is a ______.
A. rhombus

B. parallelogram

C. square

D. rectangle


Answer:

All sides of a rhombus are equal and the diagonals bisect each other at right angles. It is also applicable for square but it is a superior form of rhombus whose all angles are equal.


Question 18.

A quadrilateral whose opposite sides and all angles are equal is a
A. rectangle

B. parallelogram

C. square

D. rhombus


Answer:

A rectangle is a quadrilateral whose opposite sides and all angles are equal. It is also applicable for square but it is a superior form of rectangle whose all sides are equal.


Question 19.

A quadrilateral whose all sides, diagonals and angles are equal is a
A. square

B. trapezium

C. rectangle

D. rhombus


Answer:

A square is the only quadrilateral whose all sides, diagonals and angles are equal.


Question 20.

How many diagonals does a hexagon have?
A. 9

B. 8

C. 2

D. 6


Answer:

Number of diagonals of a polygon =


where n is the number of sides


Here n = 6


So the number of diagonals =


Question 21.

If the adjacent sides of the parallelogram are equal then parallelogram is a
A. rectangle

B. trapezium

C. rhombus

D. square


Answer:

In parallelogram the opposite sides are equal. When the adjacent sides becomes equal all the sides of the parallelogram becomes equal and hence it becomes a rhombus.


Question 22.

If the diagonals of the quadrilateral are equal and bisect each other, then the quadrilateral is a
A. rhombus

B. rectangle

C. square

D. parallelogram


Answer:

A rectangle is a quadrilateral whose diagonals are equal and bisect each other. It is also applicable for square but it is a superior form of rectangle whose all sides are equal.


Question 23.

The sum of all exterior angles of a triangle is
A. 180°

B. 360°

C. 540°

(d)720°


Answer:

The sum of all exterior angles of all polygons is equal to 3600


Question 24.

Which of the following is an equiangular and equilateral polygon?
A. square

B. rectangle

C. rhombus

D. right triangle


Answer:

A square is the only polygon whose all sides and all angles are equal.


Question 25.

Which one has all the properties of a kite and a parallelogram?
A. trapezium

B. rhombus

C. rectangle

D. parallelogram


Answer:

In a rhombus the opposite sides are parallel, diagonals bisect at right angles and all the sides are equal. So it has all the properties of a kite and a parallelogram.


Question 26.

The angles of the quadrilaterals are in the ratio 1:2:3:4, the smallest angle is
A. 72°

B. 144°

C. 36°

D. 18°


Answer:

Let the angles be x ,2x ,3x ,4x


Sum of interior angles of a quadrilateral = 3600


x + 2x + 3x + 4x = 3600


⇒ 10x = 3600


⇒ x = 360


Question 27.

In the trapezium ABCD, the measure of ∠D is


A. 55°

B. 115°

C. 135°

D. 125°


Answer:

D & A are supplementary

D + A = 1800


D = 1800-550


D = 1350


Question 28.

A quadrilateral has three acute angles. If each measures 80°, the measure of the fourth angle is
A. 150°

B. 120°

C. 105°

D. 140°


Answer:

Let the fourth angle be x


Sum of interior angles of a quadrilateral = 3600


x + 80× 3 = 3600


⇒ x = 3600-2400


⇒ x = 1200


Question 29.

The number of sides of a regular polygon where each exterior angle has a measure of 45° is
A. 8

B. 10

C. 4

D. 6


Answer:

Let the number of sides be n


sum of all exterior angles of all polygons is equal to 3600


n× 450 = 3600


⇒ n = 8


Question 30.

In a parallelogram PQRS, if ∠p= 60°, then other three angles are
A. 45°, 135°, 120°

B. 60°, 120°, 120°

C. 60°, 135°, 135°

D. 45°, 135°, 135°


Answer:

Opposite angles are equal and adjacent angles are supplementary in a parallelogram.

P = 60°


R = 60°


Q = ∠S = 1800- 60°


Q = ∠S = 1200


The three angles are 60°, 120°, 120°


Question 31.

If two angles of the parallelogram are in the ratio 2:3, then the measure of angles are
A. 72°, 108°

B. 36°, 54°

C. 80°, 120°

D. 96°, 144°


Answer:

Let the angles be 2x, 3x


The adjacent angles of a parallelogram are always supplementary and the opposite angles are always equal


2x + 3x = 1800


⇒ 5x = 1800


⇒ x = 360


So, the angles are


2× 36 = 720


3× 36 = 1080


Question 32.

If PQRS is a parallelogram, then P - R is equal to
A. 60°

B. 90°

C. 80°

D. 0°


Answer:

The opposite angles of a parallelogram are always equal and so their difference is always 00


Question 33.

The sum of the adjacent angles of a parallelogram is
A. 180°

B. 120°

C. 360°

D. 90°


Answer:

The adjacent angles of a parallelogram are always supplementary so sum is 1800


Question 34.

The angle between the two altitudes of a parallelogram through the same vertex of an obtuse angle of the parallelogram is 30°. The measure of the obtuse angle is
A. 100°

B. 150°

C. 105°

D. 120°


Answer:

BE & EF are perpendiculars from the same point


∠ EBF = 300(given)


Sum of interior angles of a quadrilateral = 3600


∠ EBF + ∠ BED + ∠ EDF + ∠ DFB = 3600


∠ EDF = 3600-(900 + 900 + 300)


∠ EDF = 1500 which is an obtuse angle.


Question 35.

In the given figure, ABCD and BCDE are parallelograms with common base DC. If BC BD, then ∠BEC=


A. 60°

B. 30°

C. 150°

D. 120°


Answer:

∠ BAC = 300 (Given)


∠ ABC = 1500(Supplementary angles)


∠ ABD = 1500-900 = 600


∠ BDC = 600(Co interior angles)


∠ BEC = 600(Opposite angles)


Question 36.

Length of one of the diagonals of a rectangle whose sides are 10 cm and 24 cm is
A. 25cm

B. 20cm

C. 26cm

D. 3.5cm


Answer:

By using Pythagoras theorem:


Length of diagonal = √ (102 + 242)


⇒ Length of diagonal = √676


⇒ Length of diagonal = 26cm


Question 37.

If the adjacent angles of a parallelogram are equal, then the parallelogram is a
A. rectangle

B. trapezium

C. rhombus

D. any of the three


Answer:

In parallelogram the opposite angles are equal. When the adjacent angles become equal all the angles become equal and so it becomes a rectangle.


Question 38.

Which of the following can be four interior angles of a quadrilateral?
A. 140°, 40°, 20°, 160°

B. 270°, 150°, 30°, 20°

C. 40°, 70°, 90°, 60°

D. 110°, 40°, 30°, 180°


Answer:

Sum of interior angles of a quadrilateral = 3600

In option (a) & (d) this condition is true. But in option (d) one angle is 1800 which if considered correct the quadrilateral becomes a triangle.


Question 39.

The sum of angles of a concave quadrilateral is
A. more than 360°

B. less than 360°

C. equal to 360°

D. twice of 360°


Answer:

Sum of interior angles of a quadrilateral = 3600 for both concave and convex quadrilateral.


Question 40.

Which of the following can never be the measure of exterior angle of a regular polygon?
A. 22°

B. 36°

C. 45°

D. 30°


Answer:

Sum of exterior angles of a polygon = 3600

3600 divided by any one of the angles must be a whole number since it gives the number of sides.


But when 3600 is divided by option (a) it gives a fraction which can be the number of sides of a polygon.


Question 41.

In the figure, BEST is a rhombus. Then the value of y-x is


A. 40°

B. 50°

C. 20°

D. 10°


Answer:



BEST is a rhombus,
So, TS || BS
∠SBE = ∠BST = 40° (alternate interior angles)
As Diagonals of a rhombus bisect at right angles.
∠y = 90°

In Δ TSO,
∠STO + ∠OST = ∠EOS (Exterior angle property)
⇒ x + 40° = 90°
⇒ x = 90° - 40°
⇒ x = 50°

So, y - x = 90° -50°

=
40°


Question 42.

The closed curve which a polygon is also is
A.

B.

C.

D.


Answer:

Only in (a) the line segments don’t intersect each other where as in the others it does.


Question 43.

Which of the following is not true for an exterior angle of a regular polygon with n sides?
A. Each exterior angle =
B. Exterior angle = 180° - interior angle

C. n =

D. Each exterior angle =


Answer:

The last option is wrong because each exterior angle

=


Question 44.

PQRS is a square. PR and SQ intersect at O. Then POQ is a
A. right angle

B. straight angle

C. reflex angle

D. complete angle


Answer:

A square is a special type of rhombus whose all the angles are equal. We know that diagonals of a rhombus bisect at right angles so this is also true for a square.


Question 45.

Two adjacent angles of a parallelogram are in the ratio 1:5. Then all the angles of the parallelogram are
A. 30°, 150°, 30°,150°

B. 85°, 95°, 85°, 95°

C. 45°, 135°, 45°, 135°

D. 30°, 180°, 30°, 180°


Answer:

Let the angles be x and 5x

The adjacent angles of a parallelogram are supplementary


x + 5x = 1800


6x = 1800


⇒ x = 300


So the angles are 30°, 150°, 30°,150°


Question 46.

A parallelogram PQRS is constructed with sides QR = 6cm. PQ = 4cm and PQR = 90°. Then PQRS is a
A. square

B. rectangle

C. rhombus

D. trapezium


Answer:

In a rectangle the adjacent sides are unequal and the angle between two sides is 900.So the given parallelogram is a rectangle.


Question 47.

The angles P, Q, R and S of a quadrilateral are in the ratio 1:3:7:9. Then PQRS is a
A. parallelogram

B. trapezium with PQRS

C. trapezium with QRPS

D. kite


Answer:

Given: Angles of a quadrilateral are in the ratio 1: 3: 7: 9

Formula Used:
Sum of the angles of a quadrilateral = 3600

Let the angles be x, 3x, 7x, and 9x

Adding the angles we get,

x + 3x + 7x + 9x = 3600

⇒ 20x = 3600

⇒ x = 180

So, we have,

x = 180

3x = 540

7x = 1260

9x = 1620

Angles P, Q, R and S = 180, 540, 1260 & 1620


∠ P ,∠S & ∠Q, ∠R are supplementary


So, PQ ||RS and it’s a trapezium


Question 48.

PQRS is a trapezium in which PQSR and P = 130°, Q = 110°, then R is equal to :
A. 70°

B. 50°

C. 65°

D. 55°


Answer:

In a trapezium the adjacent angles in the non-parallel sides are supplementary

∠ R + ∠ Q = 1800


⇒ ∠ R = 1800-1100


⇒ ∠ R = 700


Question 49.

The number of sides of a regular polygon who’s each interior angle is of 135° is
A. 6

B. 7

C. 8

D. 9


Answer:

Each interior angle = 1350

Let the number of sides be n


Sum of interior angles = n×1350


Sum of interior angles is given by = (2n-4) × 900


Equating we get


(2n-4)90 = 135n


⇒ 180n-360 = 135n


⇒ 45n = 360


⇒ n = 8


Question 50.

If a diagonal of a quadrilateral bisects both the angles, then it is a
A. kite

B. parallelogram

C. rhombus

D. rectangle


Answer:

A parallelogram is a quadrilateral whose diagonal bisects both the angles. It is also true for rhombus and rectangle but in a rhombus all the sides are also equal and in a rectangle all the angles are also equal.


Question 51.

To construct a unique parallelogram, the minimum number of measurements required is
A. 2

B. 3

C. 4

D. 5


Answer:

In a parallelogram the opposite sides and opposite angles are equal. So to construct a parallelogram we need the measurements of the two adjacent sides of the parallelogram and the angle between them.


Question 52.

To construct a unique rectangle, the minimum number of measurements required is
A. 4

B. 3

C. 2

D. 1


Answer:

We only need the measurement of the length and the breadth of a rectangle to construct it. So only two measurements are required.


Question 53.

Fill in the blanks to make the statements true.

In quadrilateral HOPE, the pairs of opposite sides are____


Answer:

HO ,PE & HE ,OP

HO ,PE & HE ,OP are the opposite sides because they have no common vertices.



Question 54.

Fill in the blanks to make the statements true.

In quadrilateral ROPE, the pairs of adjacent angles are______


Answer:

∠R , ∠O; ∠O, ∠P; ∠P, ∠E; ∠E, ∠R

∠R , ∠O; ∠O, ∠P; ∠P, ∠E; ∠E, ∠R are the pair of adjacent angles because they have a common vertices.



Question 55.

Fill in the blanks to make the statements true.

In quadrilateral WXYZ, the pairs of opposite angles are___


Answer:

∠W , ∠Y ; ∠X , ∠Z

∠W , ∠Y ; ∠X , ∠Z are the pair of opposite angles because they have no common sides.



Question 56.

Fill in the blanks to make the statements true.

The diagonals of the quadrilateral DEFG are ______ and _______.


Answer:

DF & EG

DF & EG are the opposite vertices of the quadrilateral and hence they create two diagonals.



Question 57.

Fill in the blanks to make the statements true.

The sum of all _______ of a quadrilateral is 360°.


Answer:

Angles

Sum of both interior as well as exterior angles of a quadrilateral is 360°.



Question 58.

Fill in the blanks to make the statements true.

The measure of each exterior angle of a regular pentagon is ________.


Answer:

720

Each exterior angle =


where n is the number of sides


For this problem n = 5 and so each exterior angle = 720



Question 59.

Fill in the blanks to make the statements true.

Sum of the angles of a hexagon is _______.


Answer:

7200

Sum of interior angle = (2n-4)×900


where n is the number of sides


In this problem n = 6


(12-4) × 900


= 8×900 = 7200



Question 60.

Fill in the blanks to make the statements true.

The measure of each exterior angle of a regular polygon of 18 sides is ________.


Answer:

200

Each exterior angle =


where n is the number of sides


For this problem n = 18


and so each exterior angle = 200



Question 61.

The number of sides of regular polygon, where each exterior angle has a measure of 36° is _______.


Answer:

n× Each exterior angle = 3600

where n is the number of sides


For this problem each exterior angle = 360


n =


⇒ n = 10



Question 62.

Fill in the blanks to make the statements true.

is a closed curve entirely made up of the line segments. The another name for this shape is __________.


Answer:

Concave Polygon


The polygon has more than one reflex angle .So it is a concave polygon.



Question 63.

Fill in the blanks to make the statements true.

A quadrilateral that is not a parallelogram but has exactly two opposite angles of equal measure is _________.


Answer:

Kite

One pair of opposite angles are equal but the other pair of angle is not equal in a kite.



Question 64.

Fill in the blanks to make the statements true.

The measure of each angle of regular pentagon is _________.


Answer:

1080

Sum of interior angle = (2n-4) × 900


where n is the number of sides


In this problem n = 5


(10-4) × 900


= 6×900 = 5400


Each interior angle =


⇒ Each interior angle = 1080



Question 65.

Fill in the blanks to make the statements true.

The name of three-sided regular polygon is _______.


Answer:

Equilateral triangle

Equilateral triangle is a three-sided regular polygon.



Question 66.

Fill in the blanks to make the statements true.

The number of diagonals in a hexagon is ______.


Answer:

9

Number of diagonals of a polygon =


where n is the number of sides


Here n = 6


So the number of diagonals =



Question 67.

Fill in the blanks to make the statements true.

A polygon is a simplest closed curve made up of only ________.


Answer:

Line segments

A polygon is a simplest closed curve made up of only line segments which don’t intersect with each other.



Question 68.

Fill in the blanks to make the statements true.

A regular polygon is a polygon whose all sides are equal and all _____ are equal.


Answer:

angles

All the sides as well as angles are equal for regular polygon.



Question 69.

Fill in the blanks to make the statements true.

The sum of interior angles of a polygon of n sides is ______ right angles.


Answer:

2n-4

Sum of interior angle = (2n-4)×900


So Sum of interior angles is 2n-4 right angles



Question 70.

Fill in the blanks to make the statements true.

The sum of all exterior angles of a polygon is _______.


Answer:

3600

The sum of all exterior angles of any polygon is always 3600



Question 71.

Fill in the blanks to make the statements true.

_______ is a regular quadrilateral.


Answer:

Square

All the angles and sides of square are equal. So it is a regular quadrilateral



Question 72.

Fill in the blanks to make the statements true.

A quadrilateral in which a pair of opposite sides is parallel is _____.


Answer:

Trapezium

Trapezium is a in which a pair of opposite sides is parallel .



Question 73.

Fill in the blanks to make the statements true.

If all sides of a quadrilateral are equal, it is a ________.


Answer:

Rhombus

Rhombus is a quadrilateral whose all sides are equal.



Question 74.

Fill in the blanks to make the statements true.

In a rhombus diagonal intersect at _______ angles.


Answer:

Right

Since all sides are equal in a rhombus so they intersect at right angles.



Question 75.

Fill in the blanks to make the statements true.

_______ measurements can determine a quadrilateral uniquely.


Answer:

Five

We need 5 measurements to determine a quadrilateral uniquely. It can be four sides one angle or 3 sides and 2 included angle.



Question 76.

Fill in the blanks to make the statements true.

A quadrilateral can be constructed uniquely if its three sides and ______ angles are given.


Answer:

Two included

We need 5 measurements to determine a quadrilateral uniquely. It can be drawn uniquely if its three sides and two included angles are given.



Question 77.

Fill in the blanks to make the statements true.

A rhombus is a parallelogram in which _______ sides are equal.


Answer:

All

rhombus is a parallelogram in which all the sides are equal and the diagonals bisect at right angle.



Question 78.

Fill in the blanks to make the statements true.

The measure of ____ angle of concave quadrilateral is more than 180°.


Answer:

One

A concave polygon has one reflex angle which is greater than 1800



Question 79.

Fill in the blanks to make the statements true.

A diagonal of a quadrilateral is a line segment that joins two _______ vertices of the quadrilateral.


Answer:

Opposite

Diagonals are drawn by joining two opposite vertices of a quadrilateral.



Question 80.

Fill in the blanks to make the statements true.

The number of sides in a regular polygon having measure of an exterior angle as 72° is _______.


Answer:

5

Number of sides × each exterior angle = 3600


So number of sides =


⇒ Number of sides = 5



Question 81.

Fill in the blanks to make the statements true.

If the diagonals of a quadrilateral bisect each other, it is a ________.


Answer:

Parallelogram

The diagonals of a parallelogram always bisects each other.



Question 82.

Fill in the blanks to make the statements true.

The adjacent sides of a parallelogram are 5cm and 9cm. It's perimeter is ________.


Answer:

28cm

Perimeter of parallelogram = 2× (Sum of adjacent sides)


⇒ 2×14 = 28cm



Question 83.

Fill in the blanks to make the statements true.

A nonagon has _______ sides.


Answer:

9

Nonagon is a polygon having 9 sides.



Question 84.

Fill in the blanks to make the statements true.

Diagonals of a rectangle are _________.


Answer:

Equal

Diagonals of a rectangle are always equal in magnitude.



Question 85.

Fill in the blanks to make the statements true.

A polygon having 10 sides known as _________.


Answer:

Decagon

Decagon is a polygon having 10 sides.



Question 86.

Fill in the blanks to make the statements true.

A rectangle whose adjacent sides are equal becomes a ________.


Answer:

Square

If the adjacent sides of rectangle becomes equal then all the sides of the rectangle becomes equal and hence it becomes a square.



Question 87.

Fill in the blanks to make the statements true.

If one diagonal of a rectangle is 6cm long, length of the other diagonal is _______.


Answer:

6cm

The diagonals of a rectangle are always equal in magnitude.



Question 88.

Fill in the blanks to make the statements true.

Adjacent angles of a parallelogram are _____.


Answer:

Supplementary

Adjacent angles of a parallelogram always add up to 1800



Question 89.

Fill in the blanks to make the statements true.

If only one diagonal of a quadrilateral bisects the other, then the quadrilateral is known as _______.


Answer:

Kite

Only one diagonal of a kite bisects each other and the diagonals meet at right angle.



Question 90.

Fill in the blanks to make the statements true.

The trapezium ABCD with ABCD, if ∠A = 1000, then ∠D =


Answer:

800

The adjacent angles of non-parallel sides are supplementary


∠ A + ∠D = 1800


⇒ ∠D = 1800-1000


⇒ ∠D = 800



Question 91.

Fill in the blanks to make the statements true.

The polygon in which sum of all exterior angles is equal to the sum of interior angles is called ________.


Answer:

Quadrilateral

Quadrilateral is a polygon whose sum of all exterior angles is equal to the sum of interior angles.



Question 92.

State whether the statements are true (T) or false (F).

All angles of trapezium are equal.


Answer:

FALSE

In a trapezium all the angles are not equal , rather , Adjacent angles (next to each other) along the sides are supplementary. This means that their measures add up to 180 degrees.


x° + y° = 180°




Question 93.

State whether the statements are true (T) or false (F).

All squares are rectangles.


Answer:

TRUE

Every square is a rectangle because it is a quadrilateral with all four angles right angles(90°).




Question 94.

State whether the statements are true (T) or false (F).

All kites are squares.


Answer:

FALSE

All kites are not squares.


A kite is a quadrilateral (four sided shape) where the four sides can be grouped into two pairs of adjacent (next to/connected) sides that are equal length.


So, if all sides are equal, and all angles of the quadrilateral are equal, then only we have a square.



Question 95.

State whether the statements are true (T) or false (F).

All rectangles are parallelograms.


Answer:

TRUE

A parallelogram is defined as a quadrilateral (4-sided polygon) with both pairs of opposite sides parallel. A rectangle certainly fits that description. In addition, a rectangle must have 4 right angles.


So, you can say that all rectangles are parallelograms




Question 96.

State whether the statements are true (T) or false (F).

All rhombuses are squares.


Answer:

FALSE

A rhombus is a quadrilateral with all sides equal in length.


A square is a quadrilateral with all sides equal in length and all interior angles right angles.


Thus a rhombus is not a square unless the angles are all right angles.



Question 97.

State whether the statements are true (T) or false (F).

Sum of all the angles of a quadrilateral is 180°.


Answer:

FALSE

Sum of all the angles of a quadrilateral is 360°.


Because ,the quadrilateral can be divided into 2 triangles and sum of angles of each of the triangles is 180°.


⸫ when we join these 2 triangles to get back the original quadrilateral then the sum of all the angles of the quadrilateral is sum of angles of both the triangles ie. 180°(sum of angles of triangle1) + 180° (sum of angles of triangle2) = 360° (sum of angles of quadrilateral)




Question 98.

State whether the statements are true (T) or false (F).

A quadrilateral has two diagonals.


Answer:

TRUE

A diagonal is a line segment connecting 2 non consecutive vertices of a polygon , ie. A line segment drawn from one vertex of a quadrilateral to the opposite vertex is called a diagonal of the quadrilateral.


So, as we can see , we can draw only 2 such line segments.


⸫ A quadrilateral can have only two diagonals.




Question 99.

State whether the statements are true (T) or false (F).

Triangle is a polygon whose sum of exterior angles is double the sum of interior angles.


Answer:

TRUE

We know that,


Sum of Interior angles of Polygon = 180(n-2)
Sum of Exterior angles of Polygon = 360
Here, for triangle , n=3,ie. triangle


So, Sum of Interior angles of triangle = 180(n-2)° = 180(3-2)° = 180°


And ,Sum of Exterior angles of triangle = 360°


⸫ we can say that ,


2 × Sum of Interior angles of triangle = Sum of Interior angles of triangle


2 × 180° = 360°



Question 100.

State whether the statements are true (T) or false (F).

is a polygon.


Answer:

TRUE



Question 101.

State whether the statements are true (T) or false (F).

A kite is not a convex quadrilateral.


Answer:

FALSE

A convex polygon is a simple polygon (not self-intersecting) in which no line segment between two points on the boundary ever goes outside the polygon. Equivalently, it is a simple polygon whose interior is a convex set.


⸫ Kite is a convex polygon.


*KITE*



Question 102.

State whether the statements are true (T) or false (F).

The sum of interior angles and the sum of extreme angles taken in an order are equal in case of quadrilaterals only.


Answer:

TRUE

We know that,


Sum of Interior angles of Polygon = 180(n-2)
Sum of Exterior angles of Polygon = 360


Here, we have n=4


⸫ Sum of Interior angles of Polygon = 180(4-2)=360°


And Sum of Exterior angles of Polygon = 360


⸫ The sum of interior angles and the sum of extreme angles taken in an order are equal in case of quadrilaterals only.



Question 103.

State whether the statements are true (T) or false (F).

If the sum of interior angles is double the sum of exterior angles taken in an order of a polygon. then it is hexagon.


Answer:

TRUE

In a hexagon number of sides = 6.


∴ Sum of the interior angles of a hexagon = (2n - 4) x 90°


= (2 x 6) - 4) x 90° = 8 x 90° = 720°. -------(1)


Sum of the exterior angles of a hexagon = 360°.


Given that 2 times the sum of the exterior angles of a hexagon ie. 2 x 360°= 720° -----(2)


from (1) and (2) we get


∴ If the sum of interior angles is double the sum of exterior angles taken in an order of a polygon, then it is hexagon.



Question 104.

State whether the statements are true (T) or false (F).

A polygon is regular if all of its sides are equal.


Answer:

TRUE

A regular polygon is a polygon that is equiangular (all angles are equal in measure) and equilateral (all sides have the same length).



Question 105.

State whether the statements are true (T) or false (F).

Rectangle is a regular quadrilateral.


Answer:

FALSE

As we know , A regular polygon is a shape whose sides are all the same length, and whose interior angles are all the same measure. A quadrilateral is a polygon with four sides. So a regular quadrilateral is a shape that has four equal sides, with all the interior angles equal., and in a rectangle , only the angles are equal , all the side are not equal , only opposite sides are equal.


⸫ Rectangle is not a regular quadrilateral.



Question 106.

State whether the statements are true (T) or false (F).

If diagonals of a quadrilateral are equal, it must be a rectangle.


Answer:

FALSE



It is not required that the quadrilateral must be a rectangle , if its diagonals are equal.


In the above picture , we can see that in both the figures , both diagonals are each 5 units long, and the quadrilateral is an isosceles trapezium.


If the diagonals of a quadrilateral are equal the figure could be a rectangle, a square or an isosceles trapezium.



Question 107.

State whether the statements are true (T) or false (F).

If opposite angles of a quadrilateral are equal, it must be parallelogram.


Answer:

TRUE


Let ABCD be a parallelogram, with A = α and B = β.


We have to Prove that C = α and D = β.


α + β = 180° (co-interior angles, AD || BC),


C = α (co-interior angles, AB || DC)


D = β (co-interior angles, AB || DC).



Question 108.

The interior angles of the triangle are in the ratio 1:2:3, then the ratio of its exterior angles is 3:2:1.


Answer:

False,


Given:


Ratio of interior angles = 1:2:3


Let the interior angles be x, 2x and 3x


Now, the sum of the interior angles of the triangle are 1800


⇒ x+ 2x + 3x = 1800


⇒ 6x = 1800


⇒ x =


⇒ x = 300


Therefore, the interior angles are: 300, 600 and 900.


Now, the exterior angles will be found by subtracting from 1800 because they form a linear pair.


The exterior angles are: 1500, 1200 and 900.



Question 109.

State whether the statements are true (T) or false (F).

is a concave pentagon.


Answer:

FALSE

The given figure is not a pentagon because it has 6 sides.



Question 110.

State whether the statements are true (T) or false (F).

Diagonals of a rhombus are equal and perpendicular to each other.


Answer:

FALSE


Consider rhombus ABCD,


You know that , AB=BC=CD=AD


Now , in ΔAED and ΔCED,


EA = EC (diagonals of a parallelogram bisect each other)


ED= ED (common)


AD=CD


⸫ ΔAED is congruent to ΔCED (SSS)


This gives that AED = CED (CPCT)


But, AED + CED = 180° (linear pair)


So , 2 × AED = 180°


AED = 90°


So , the diagonals of rhombus are only perpendicular to each other.


⸫ the diagonals of rhombus are perpendicular but not equal.



Question 111.

State whether the statements are true (T) or false (F).

Diagonals of a rectangle are equal.


Answer:

TRUE


Given ABCD is a rectangle


then AC and BD are diagonals


then in ΔABC and ΔBCD,


b is common angle


BC is common side


AB = CD


so by SAS congruency,


Δ ABC is congruent to ΔBCD


so by cpct,


AC = BD


so ,diagonals are equal.



Question 112.

State whether the statements are true (T) or false (F).

Diagonals of a rectangle bisect each other at right angles.


Answer:

TRUE


In rectangle ABCD, diagonals bisect the angles.
Consider ΔAOD and ΔBOC
AD = BC (ABCD is a rectangle)
∠AOD = ∠BOC (Vertically opposite angles)
∠OAD = ∠OCB = 45° (Diagonals bisect the angles)
ΔAOD ≅ ΔBOC (AAS congruence criterion)
Therefore, OA = OC and OB = OD
Thus the diagonals bisect each other in a rectangle.



Question 113.

State whether the statements are true (T) or false (F).

Every kite is a parallelogram.


Answer:

FALSE

Kite is a quadrilateral that has 2 adjacent equal sides, that is upper and lower side , whereas in parallelogram , opposite side should be equal.


⸫every kite is not a parallelogram.



Question 114.

State whether the statements are true (T) or false (F).

Every trapezium is a parallelogram.


Answer:

FALSE

In a parallelogram, both the pairs of sides should be parallel. So , in a trapezium , only one pair of sides is parallel that is it doesn’t fulfill the conditions for parallelogram.



Question 115.

State whether the statements are true (T) or false (F).

Every parallelogram is a rectangle.


Answer:

FALSE

In a rectangle, all the angles should be equal to 90°. So , all the parallelograms may not have all the angles as 90°.



Question 116.

State whether the statements are true (T) or false (F).

Every trapezium is a rectangle.


Answer:

FALSE

In a rectangle , all the angles should be equal to 90°. So , all the trapeziums may not have all the angles as 90° , even if they have a pair of parallel sides.



Question 117.

State whether the statements are true (T) or false (F).

Every rectangle is a trapezium.


Answer:

FALSE

A trapezium is defined to be a quadrilateral that has exactly one pair of parallel sides. Whereas rectangle has 2 pairs of parallel sides. So every rectangle is not a trapezium.



Question 118.

State whether the statements are true (T) or false (F).

Every square is a rhombus.


Answer:

TRUE

In rhombus, all the sides should be equal and the diagonals should be perpendicular to each other.


This condition is fulfilled by the square.



Question 119.

State whether the statements are true (T) or false (F).

Every square is a parallelogram.


Answer:

TRUE

In a parallelogram, opposite pairs of sides should be equal and opposite angles should also be equal. These conditions are fulfilled by square.



Question 120.

State whether the statements are true (T) or false (F).

Every square is a trapezium.


Answer:

FALSE

A trapezium is defined to be a quadrilateral that has exactly one pair of parallel sides. Whereas square has 2 pairs of parallel sides. So every square is not a trapezium.



Question 121.

State whether the statements are true (T) or false (F).

Every rhombus is a trapezium.


Answer:

FALSE

A trapezium is defined to be a quadrilateral that has exactly one pair of parallel sides. Whereas rhombus has 2 pairs of parallel sides. So every rhombus is not a trapezium.



Question 122.

State whether the statements are true (T) or false (F).

A quadrilateral can be drawn if only measure of four sides are given.


Answer:

FALSE

To draw a quadrilateral, we need at least 2 angles as well.



Question 123.

State whether the statements are true (T) or false (F).

A quadrilateral can have all four angles as obtuse.


Answer:

FALSE

As we know that the sum of all the interior angles of the quadrilateral = 360°.


And , if all the 4 angles are obtuse then the above property is violated.


So, A quadrilateral cannot have all four angles as obtuse.



Question 124.

State whether the statements are true (T) or false (F).

A quadrilateral can be drawn if all the four sides and one diagonal is given.


Answer:

TRUE


Let AB,BC,CD,AD(sides) and AC(diagonal) be given.


Draw ΔABC using SSS construction.


Now, we have to locate the 4th point D. this ‘D’ would be on the side opposite to B with reference to AC.


So, with A as centre draw an arc of radius of length equal to AD.


Now, with C as centre draw an arc of radius of length equal to CD.


The intersection of these 2 arcs is D. Mark D and complete ABCD



Question 125.

State whether the statements are true (T) or false (F).

A quadrilateral can be drawn when all the four angles and one side is given.


Answer:

FALSE

To construct a quadrilateral, we need at least 3 sides.



Question 126.

State whether the statements are true (T) or false (F).

A quadrilateral can be drawn if all four sides and one angle is known.


Answer:

FALSE

To construct a quadrilateral, we need at least 2 angles.



Question 127.

State whether the statements are true (T) or false (F).

A quadrilateral can be drawn if three sides and two diagonal diagonals are given.


Answer:

TRUE


Here, let BC,AD,CD(sides) are given and AC , BD (diagonals)are also given.


Draw ΔACD by using SSS construction.


With D as centre, draw an arc of radius of length equal to BD.


With C as centre, draw an arc of radius of length equal to BC.


The intersection of these 2 arcs is B. Mark B and complete ABCD.



Question 128.

State whether the statements are true (T) or false (F).

If diagonals of a quadrilateral bisect each other. it must be a parallelogram.


Answer:

FALSE


It is not required that the quadrilateral must be a parallelogram , if its diagonals are equal.


In the above picture , we can see that in both the figures, both diagonals are each 5 units long, and the quadrilateral is an isosceles trapezium.



Question 129.

State whether the statements are true (T) or false (F).

A quadrilateral can be constructed uniquely if three angles and any two sides are given.


Answer:

TRUE

Let AB, BC(sides) and A,B,C are given.



Draw AB and then B.


From B, draw BC.


At C, draw C.


At M, draw A and mark the point of intersection of these 2 angles as D.


So, we get the required quadrilateral ABCD.



Question 130.

State whether the statements are true (T) or false (F).

A parallelogram can be constructed uniquely if both diagonals and the angle between them is given.


Answer:

TRUE

Mark a point A and draw a line through A.


From A, draw an arc of radius of length equal to one diagonal to cut the above line at C.


Bisect AC at O.


From A and C, draw arcs of radius more than half the length of AC on both sides, Let they cut at X and Y. XY is the perpendicular bisector of AC. It cuts AC at O.


From O, draw a line at the given angle to AC on both sides.


From O, draw an arc of radius of half the length of another diagonal on both sides of AC to cut the above line at B and D.


Join AB,BC,CD,AD.




Question 131.

State whether the statements are true (T) or false (F).

A rhombus can be constructed uniquely if both diagonals are given.


Answer:

TRUE

Here only 2 measurements of the rhombus are given ie. The diagonals.


However , since it is a rhombus , we can find more help from its properties.


The diagonals of a rhombus are perpendicular bisectors of one another.


So, first draw AC (any one diagonal) and then construct its perpendicular bisector. Let them meet at E. Cut off half the length of second diagonal on either side of the drawn bisector.


You now get B and D.


Similarly, get A and C, draw the rhombus now.




Question 132.

The diagonal of a rhombus is 8cm and 15 cm. Find its side.


Answer:

Given, the diagram below:


diagonals of a rhombus, d1 = 8cm


d2 = 15cm


Divide d1 and d2 in two equal halves.


We will get four right angled triangles


Now, the base of each triangle would be, d1/2 = 8/2 = 4cm


And perpendicular would be, d2/2 = 15/2 = 7.5cm


Now, we will find the hypotenuse of each right angled


triangle.


Hence, hypotenuse = side of rhombus








Question 133.

Two adjacent angles of a parallelogram are in the ratio 1:3. Find its angles.


Answer:

Given, ratio of the adjacent angles of a parallelogram is 1:3

⇒ By the property of parallelogram, the sum of adjacent angles of a parallelogram is 180°.


⇒ Let the adjacent angles are ∠A and ∠B.


∠A = x


∠B = 3x


∠A + ∠B = x + 3x {∠A + ∠B = 180


4x = 180 ̇


x = 45


⇒ ∠A = 45


⇒∠B = 45×3 = 135



Question 134.

Of the four quadrilaterals- square, rectangle, rhombus and trapezium- one is somewhat different from the others because of its design. Find it and gave justification.


Answer:

According to question, we have four quadrilaterals- square,

Rectangle, rhombus and trapezium.


By the property of parallelogram, a parallelogram is a quadrilateral whose opposite sides are always parallel.


But in case of trapezium, only one pair of opposite sides are parallel. Hence, it is not a parallelogram.


it is clear from the above points that trapezium is different from square, rectangle and rhombus.



Question 135.

In a rectangle ABCD. AB = 25cm and BC = 15cm. In what ration does the bisector of C divides AB?


Answer:

The figure is given below:


Given, a rectangle ABCD


AB = 25cm


BC = 15cm


Bisector of ∠C divides AB i.e. ∠BCE = 45


⟹ By angle sum property of triangle.


∠BEC = 45


⟹ BC = BE, because sides having equal angles are equal.


BE = 15cm


And AE = AB-BE = 25-15


AE = 10cm


AE:BE = 10:15


AE:BE = 2:3



Question 136.

PQRS is a rectangle. The perpendicular ST from S on PR divides S in the ratio 2:3. Find TPQ.


Answer:

The figure is given below:


PQRS is a rectangle. The perpendicular ST from S on PR divides angle S in the ratio 2:3.


∠PSR = 90


⟹ It is given that, the perpendicular ST from S on PR divides angle S in the ratio 2:3.


⟹ divide the 90° angle into the ratio 2:3.


2x + 3x = 90


5x = 90


x = 18


⟹ therefore, 2x = 2×18 = 36 and 3x = 3×18 = 54


now, ∠PST = 36 and


∠TSR = 54 = ∠TSQ + ∠QSR


∠PST = 36


∠TSR = 54 = ∠TPS


Hence, ∠TPQ = ∠SPQ-∠TPS = 90-54 = 36



Question 137.

A photo frame is in the shape of quadrilateral. With one diagonal longer than the other. Is it a rectangle? Why or why not?


Answer:

A photo frame is in the shape of quadrilateral with one diagonal longer than the other. So, That quadrilateral-shaped frame is not in shape of rectangle. As we know rectangle have equal diagonals.



Question 138.

The adjacent angles of a parallelogram are (2x -4)° and (3x - 1) °. Find the measures of all angles of the parallelogram.


Answer:

Given, adjacent angles are (2x-4) and (3x-1)

⟹ (2x-4) + (3x-1) = 180


⟹ (5x-5) = 180


⟹ 5(x-1) = 180


⟹ x-1 = 36


⟹ x = 37


⟹ First angle = 2x-4 = (2×37)-4 = 70


⟹ Second angle = 3x-1 = (3×37)-1 = 110



Question 139.

The point of intersection of diagonals of a quadrilateral divides one diagonal in the ration 1:2. Can it be a parallelogram? Why or why not?


Answer:

No, it cannot be a parallelogram because the diagonal of a parallelogram are always bisect each other i.e. in the ratio 1:1.



Question 140.

The ration between exterior angle and interior angle of a regular polygon is 1:5. Find the number of sides of the polygon.


Answer:

Given, the ratio between exterior angle and interior angle is

1:2.


Let, exterior angle = x


And, interior angle = 5x


Sum of exterior and interior angle is equal to 180.


Hence, x + 5x = 180


6x = 180


x = 30


⟹Total measure of all the exterior angle = 360


⟹Measure of each exterior angle = 30


Therefore, the number of all exterior angles


Hence, the polygon has 12 sides.



Question 141.

Two sticks each of length 5cm are crossing each other such that they bisect each other. What shape is formed by joining their end points? Give reason.


Answer:

Given, two sticks each of length 5cm i.e. equal in length.

If the diagonal of a quadrilateral are equal and bisects each


Other then the quadrilateral is a rectangle. Hence, the shape


Formed by joining given two sticks will be a rectangle.



Question 142.

Two sticks each of length 7cm are crossing each other such that they bisect each other at right angle. What shape is formed by joining their end points? Give reasons.


Answer:

Given, two sticks each of length 7cm i.e. equal in length.

If the diagonal of a quadrilateral are equal and bisects each


Other at right angle then the quadrilateral is a rhombus. Hence, the shape formed by joining given two sticks will be a rhombus.



Question 143.

A playground in the town is in the form of a kite. The perimeter is 106 metres. If one of its sides is 23 metres. What are the lengths of other three sides?


Answer:

The kite has four sides. There are exactly two distinct consecutive pairs of sides of equal length.

Let two different length be A and B.


Then the perimeter = 2A + 2B _______(i)


Given, perimeter = 106m


And one side i.e = 23m


According to Eq.(i), (2 × 23) + 2B = 106


2B = 60


B = 30


Hence, all sides are 23, 23, 30, 30.


Question 144.

In rectangle READ. Find ∠EAR, ∠ RAD and ∠ROD.



Answer:

Given, ∠ROE = 60

According to given figure, ∠AOE = 120, ∠AOD = 60 and ∠ROD = 120.


⟹In triangle AOE, consider ∠EAR = ∠DEA = x


∠AOE + ∠EAR + ∠DEA = 180


x + x + 120 = 180


2x + 120 = 180


2x = 60


x = 30, i.e. ∠EAR = 30


⟹In triangle AOD, consider ∠RAD, = ∠EDA = y


∠RAD + ∠EAR + ∠AOD = 180


y + y + 60 = 180


2y = 120


y = 60, i.e.∠RAD = 60.



Question 145.

In rectangle PAIR. Find ∠ARI, ∠RMI and ∠PMA.


Answer:

Given, ∠RAI = 35

⟹In ∆ARI,


∠A + ∠R + ∠I = 180


35 + ∠ARI + 90 = 180


∠ARI = 55


⟹In ∆RMI,


∠R + ∠M + ∠I = 180


∠ARI + ∠RMI + ∠ARI = 180 {∠ARI = ∠MIR = 55}


(2×55) + ∠RMI = 180


∠RMI = 70


And, ∠PMA = 180-∠RMI


∠PMA = 180-70


∠PMA = 110


Question 146.

In parallelogram ABCD, find∠ B, ∠C and ∠D.



Answer:

Given, ∠A = 80

⟹The sum of the adjacent angles of a parallelogram is 180


Hence, ∠A + ∠B = 180


∠B = 180-80


∠B = 100


⟹The opposite angles of a parallelogram are equal.


Hence, ∠C = ∠A = 80


And, ∠D = ∠B = 100



Question 147.

In parallelogram PQRS. O is the mid-point of SQ. Find ∠S, ∠R. PQ, Qr and diagonal PR.



Answer:

Given:

∠RQY = 60°


∵ ∠RQY and ∠RQP form a linear pair


⇒ ∠RQP = 180° - ∠RQY = 120°


∴ ∠RQP =120°


Now, in a parallelogram, the opposite sides are equal,


⇒ ∠RQP = ∠S = 120°


Similarly, ∠P = ∠R


Now, from the angle sum property of a quadrilateral,


∠P + ∠R + ∠Q + ∠S = 360°


⇒ ∠P + ∠R + 120° + 120° = 360°


⇒ 2∠P = 120°


⇒ ∠P = 60°


⇒ ∠R = 60°


Now,


Opposite sides of the parallelogram are equal.


⇒ SR = PQ = 15 cm


Also, PS = QR = 11 cm


And, the diagonals of the parallelogram bisect each other.


Hence, PR = 2×PQ = 2×6 = 12 cm.



Question 148.

In rhombus BEAM. Find AME and AEM.



Answer:

In the rhombus,

∠BAM = 700


Also, we know that the diagonals of a rhombus bisect at 900


∴ ∠AOM = 90


Now, in ΔAOM,


∠AOM + ∠OMA + ∠MOA = 1800


⇒ 90 + ∠OMA + 70 = 1800


⇒ ∠AME = ∠OMA = 200


Also,


The sides in the rhombus are equal.


Ans, we know, equal sides make equal angles.


⇒ ∠AEM = 200



Question 149.

In parallelogram FIST. Find SFT, OST and STO.



Answer:

Given, ∠TOF,∠TIS and ∠TIF

⟹In ∆TOF,


∠T + ∠O + ∠F = 180


25 + 110 + ∠SFT = 180


∠SFT = 180-135


∠SFT = 45


⟹In ∆TOS,


∠T + ∠O + ∠S = 180


35 + (180-110) + ∠OST = 180


35 + 70 + ∠OST = 180


∠OST = 180-105


∠OST = 75


∠STO = ∠T(in triangle SOT) = 35



Question 150.

In the given parallelogram YOUR, ∠RUO = 120° ad OY is extended to point S such that ∠SRY = 50°. Find ∠YSR.



Answer:

Given, ∠RUO = 120 and ∠SRY = 50

⟹The opposite angles of a parallelogram are equal.


Hence, ∠RYO = 120


⟹In ∆YSR,


∠Y + ∠R + S = 180


(180-120) + 50 + ∠YSR = 180


110 + ∠YSR = 180


∠YSR = 70



Question 151.

In kite WEAR, ∠WEA = 70° and ∠ARW = 80°. Find the remaining two angles.



Answer:

In ∆ARW,

∠R + ∠A + ∠W = 180


⟹Let ∠A = ∠W = x


80 + 2x = 180


2x = 180-80


x = 50


⟹In ∆WEA,


∠W + ∠E + ∠A = 180


⟹Let ∠W = ∠A = y


2y + 70 = 180


2y + 180-70


y = 55


⟹Hence, ∠RWE = ∠RAE = (x + y)


= (50 + 55)


= 105



Question 152.

A rectangular MORE, is shown below:



Answer the following questions by giving appropriate reason.

(i) Is RE = OM? (ii) Is MYO = RXE?

(iii) Is MOY = REX? (iv) Is ∆MYO = ∆RXE?

(v) Is MY = RX?


Answer:

(i) Yes,

∵ MORE is a rectangle.


And, the opposite sides of the rectangle are equal.


∴ RE = OM


(ii) Yes,


In the MORE rectangle,


MY and RX are perpendicular to OE


⇒ ∠RXO = ∠RXE = ∠MYE = ∠MYO = 900


∴ ∠MYO = ∠RXE


(iii) Yes,


∵ in rectangle MORE, RE||OM and EO is transveral.


From the property of alternate interior angles being equal.


∴ ∠MOE = ∠OER


⇒ ∠MOY = ∠REX


(iv) Yes,


In, ΔMYO and Δ RXE,


MO = RE


∠MOY = ∠REX


∠MYO = ∠RXE


∴ ΔMYO ≅ ΔRXE


(v) Yes.


Corresponding parts of congruent triangles are equal.



Question 153.

In parallelogram LOST, SN Ol and SM LT. Find STM, SON and NSM.



Answer:

⟹In ∆STM,

∠S + ∠T + ∠M = 180


40 + ∠STM + 90 = 180


∠STM = 180-130 = 50


∠STM = ∠SON (these are opposite angles).


∠SON = 50


∠SON and ∠OST are adjacent angles.


⟹Hence, ∠SON + ∠NSO + ∠NSM + ∠MST = 180


50 + (180-(90 + 50)) + ∠NSM + 40 = 180


∠NSM = 140-90


∠NSM = 50



Question 154.

In trapezium HARE. EP and RP are bisectors of E and R respectively. find ∠HAR and ∠EHA.



Answer:

Adjacent angles along a side of a trapezium are supplementary.

Hence, ∠R + ∠A = 180 ________(i)


Similarly, ∠E + ∠H = 180 ________(ii)


According to given data in question,


The complete ∠R = 2×30 = 60


And ∠E = 2×25 = 50


Because, EP and RP are bisectors of E and R respectively.


By Eq (i) and (ii),


∠A = 180-60 = 120


∠H = 180-50 = 130



Question 155.

In parallelogram MODE, the bisector of ∠M and O meet at Q. Find the measure of ∠MQO.


Answer:

Let MODE be the parallelogram and Q be the point of intersection of the bisector of ∠M and ∠O


The figure is attached below:



Now, in a parallelogram, the adjacent angles are supplementary.


∴ ∠EMO + ∠DOM = 180°


⇒ 1/2 (∠EMO + ∠DOM) = 1/2 180°


⇒ 1/2∠EMO + 1/2∠DOM = 1/2 180°


∠QMO + ∠QOM = 90°


Now, in ΔMOQ,


∠QMO + ∠QOM + ∠MQO = 1800


⇒ 900 + ∠MQO = 1800


⇒ ∠MQO = 900



Question 156.

A playground is in the form of a rectangular ATEF, two players are standing at the points of F and B where EF = EB. Find the values of x and y.



Answer:

EBF formed a isosceles triangle.

⟹Hence, ∠EBF = ∠EFB = 45


⟹According to question,


∠EBF + ∠x = 180


∠x = 180-45 = 135


⟹And ∠EFB + y = 90


∠y = 90-45 = 45



Question 157.

In the following figure of a ship. ABDH and CEFG are two parallelograms. Find the value of x.



Answer:

⟹In llgm ABDH,

∠D = ∠BAH = 180-130(adjacent angles)


⟹In llgm CEFG,


∠C = ∠GCE = ∠GFE = 30(opposite angles)


⟹Hence, in ∆CDX,


∠C + ∠D + ∠x = 180


30 + 130 + ∠x = 180


∠x = 180-160 = 20



Question 158.

A rangoli has been drawn on a floor of house. ABCD and PQRS both are in the shape of a rhombus ABCD.



Answer:

In Rhombus ABCD,


AO = OP + PA = 2+2 = 4 units.


And, OB = OQ + QB = 2 + 1 = 2 units.


Now,


We know that the diagonals of the rhombus bisect at 900


∴ in ΔOAB,


AB2 = OA2 + OB2


⇒ AB2 = 42 + 32


⇒ AB = √25


⇒ AB = 5 units.


Now, AB is also the diameter of the semi-circle.


∴ radius of the circle will be 2.5 units.



Question 159.

ABCDE is a regular pentagon. The bisector of angle A meets the side CD at M. Find AMC



Answer:

The figure is attached below:


I have circumscribed the regular Pentagon with a circle. Since, the 360° of the circle is divided equally by the pentagon to five parts.


⇒ ∠COD =


Using the properties of circle,


∠CAD = 1/2 ∠COD


⇒ ∠CAD = 1/2 720


∠CAD = 360


Now, in ∆ACD.


36° + ∠ACD + ∠ADC = 180°


Since, ∆ACD is an isosceles ∆,


36° + 2×∠ACD = 180°


∠ACD = 72°


Now, in ∆AMC.


∠MAC = 1/2 ∠CAD = 18°


Now,


∠MAC + ∠AMC + ∠ACM = 180°


18° + ∠AMC + 72° = 180°


∠AMC = 90°



Question 160.

Quadrilateral EFGH is a rectangular in which J is the point of intersection of the diagonals. Find the value of x if JF = 8x + 4 and EG = 24x-8.


Answer:


By the property of rectangle, the length of both the diagonals are equal.


Hence, FH = EG


2(JF) = EG


2(8x + 4) = (24x-8)


16x + 8 = 24x-8


8x = 16


x = 2