MCQs on Class 8 Understanding Quadrilaterals

MCQs on Class 8 Understanding Quadrilaterals

Multiple Choice Questions (MCQs) are available for Class 8 Understanding Quadrilaterals chapter. Each problem consists of four multiple options, out of which one is the correct answer. Students have to solve the problem and select the correct answer.

 

 

1. Which of the following is not a quadrilateral?

A. Square

B. Rectangle

C. Triangle

D. Parallelogram

Answer: C

Explanation: A quadrilateral is a four-sided polygon but triangle is a three-sided polygon.

 

 

2. Which of the following quadrilaterals has two pairs of adjacent sides equal and its diagonals intersect at 90 degrees?

A. Square

B. Kite

C. Rhombus

D. Rectangle

Answer: B

 

 

3. Which one of the following is a regular quadrilateral?

A. Square

B. Trapezium

C. Kite

D. Rectangle

Answer: A

Explanation: A square has all its sides equal and angles equal to 90 degrees.

 

 

4. If AB and CD are two parallel sides of a parallelogram, then:

A. AB>CD

B. AB<CD

C. AB=CD

D. None of the above

Answer: C

 

 

5. The perimeter of a parallelogram whose parallel sides have lengths equal to 12 cm and 7 cm is:

A. 21 cm

B. 42 cm

C. 19 cm

D. 38 cm

Answer: D

Explanation: Perimeter of parallelogram = 2 (Sum of Parallel sides)

P = 2 (12 + 7)

P = 2 (19)

P = 38 cm

 

 

6. If ∠A and ∠C are two opposite angles of a parallelogram, then:

A. ∠A > ∠C

B. ∠A = ∠C

C. ∠A < ∠C

D. None of the above

Answer: B

Explanation: Opposite angles of a parallelogram are always equal.

 

 

7. If ∠A and ∠B are two adjacent angles of a parallelogram. If ∠A = 70°, then ∠B = ?

A. 70°

B. 90°

C. 110°

D. 180°

Answer: C

Explanation: The adjacent angles of parallelogram are supplementary.

∠A + ∠B = 180°

70° + ∠B = 180°

∠B = 180 – 70° = 110°

 

 

8. ABCD is a rectangle and AC & BD are its diagonals. If AC = 10 cm, then BD is:

A. 10 cm

B. 5 cm

C. 15 cm

D. 20 cm

Answer: A

Explanation: The diagonals of a rectangle are always equal.

 

 

9. Each of the angles of a square is:

A. Acute angle

B. Right angle

C. Obtuse angle

D. 180 degrees

Answer: B

Explanation: All the angles of square is at right angle.

 

 

10. The quadrilateral whose diagonals are perpendicular to each other is:

A. Parallelogram

B. Rectangle

C. Trapezium

D. Rhombus

Answer: D

 

 

11. Which of the following is not a regular polygon?

A. Square
B. Equilateral triangle
C. Rectangle
D. Regular hexagon

Answer: C. Rectangle
Explanation: A regular polygon is both equiangular and equilateral. But all four sides of a rectangle are not equal, thus it is not a regular polygon.

 

 

12. If the two angles of a triangle are 80° and 50°, respectively. Find the measure of the third angle.
A. 50°
B. 60°
C. 70°
D. 80°

Answer: A. 50°

Explanation: By the angle sum property of triangle, we know that;
Sum of all the angles of a triangle = 180°
Let the unknown angle be x
80° + 50° + x = 180°
x = 180° – 130°
x = 50°

 

 

13. In a parallelogram ABCD, angle A and angle B are in the ratio 1:2. Find the angle A.
A. 30°
B. 45°
C. 60°
D. 90°

Answer: C.60°

Explanation: As we know, the sum of adjacent angles of a parallelogram is equal to 180° and opposite angles are equal to each other.
Thus, in parallelogram ABCD angle A and angle B are adjacent to each other
Let angle A = x and angle B = 2x.
So, x + 2x = 180°
3x = 180°
x = 60°

 

 

14. The angles of a quadrilateral are in ratio 1:2:3:4. Which angle has the largest measure?
A. 120°
B. 144°
C. 98°
D. 36°

Answer: B.144°

Explanation: Suppose, ABCD is a quadrilateral.
Let angle A is x
Then,
x + 2x + 3x + 4x = 360° [Angle sum property of quadrilateral] 10x = 360°
x = 36°
Hence, the greatest angle is 4x = 4 x 36 = 144°

 

 

15. The length and breadth of a rectangle is 4 cm and 2 cm respectively. Find the perimeter of the rectangle.
A. 12 cm
B. 6 cm
C. 8 cm
D. 16 cm

Answer: A. 12 cm
Explanation: Given, length of rectangle is 4 cm
Breadth of rectangle = 2cm
By the formula of perimeter of rectangle, we know that;
Perimeter = 2 (Length + Breadth)
P = 2(4+2)
P = 2 x 6
P = 12 cm

 

 

16. The diagonals of a rectangle are 2x + 1 and 3x – 1, respectively. Find the value of x.
A. 1
B. 2
C. 3
D. 4

Answer: B.2

Explanation: The diagonals of a rectangle are equal in length.
2x + 1 = 3x -1
1 + 1 = 3x – 2x
2 = x
Thus, the value of x is 2.

 

 

17. The diagonals of a kite:
A. Bisects each other
B. Are perpendicular to each other
C. Does not bisect each other
D. None of the above

Answer: B. Are perpendicular to each other

Explanation: The diagonals of a kite are perpendicular to each other. They intersect at 90 degrees but does not bisect.

 

 

18. A rhombus has a side length equal to 5 cm. Find its perimeter.
A. 25
B. 10
C. 20
D. 30

Answer: C. 20

Explanation: A rhombus is a parallelogram that has all its four sides equal. Thus, the perimeter of rhombus,
P = 4 x side-length
P = 4 x 5
P = 20 cm

 

 

19. ABCD is a parallelogram. If angle A is equal to 45°, then find the measure of its adjacent angle.
A. 135°
B. 120°
C. 115°
D. 180°

Answer: A.135°

Explanation: The adjacent angles of a parallelogram sums up to 180°.
Thus,
45° + x = 180°
x = 180° – 45°
x = 135°

 

 

20. The kite has exactly two distinct consecutive pairs of sides of equal length.
A. True
B. False

Answer: A. True

Explanation: A kite is a quadrilateral that has exactly two distinct consecutive pairs of sides of equal length.