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# Exercise 7.4: Multiple choice questions

Maths : Mensuration: Book Back, Exercise, Example Numerical Question with Answers, Solution: Exercise 7.4: Multiple choice questions: One Mark Choose the correct Answers

Mensuration

Exercise 7.4

Multiple choice questions

1. The semi-perimeter of a triangle having sides 15 cm, 20 cm and 25 cm is

(1) 60 cm

(2) 45 cm

(3) 30 cm

(4) 15 cm

Solution:

s = [15+20+25] / 2 = 60/2 = 30

2. If the sides of a triangle are 3 cm, 4 cm and 5 cm, then the area is

(1) 3 cm2

(2) 6 cm2

(3) 9 cm2

(4) 12 cm2

Solution:

s = 3+4+5 /2 = 12/2=6

A = ŌłÜ[6(6 ŌłÆ 3)(6 ŌłÆ 4)(6 ŌłÆ 5)] = ŌłÜ[6 ├Ś 3 ├Ś 2 ├Ś 1] = ŌłÜ36 = 6 sq. cm

3. The perimeter of an equilateral triangle is 30 cm. The area is

(1) 10ŌłÜ3 cm2

(2) 12ŌłÜ3 cm2

(3) 15ŌłÜ3 cm2

(4) 25ŌłÜ3 cm2

Solution:

3a=30

a = 10 cm

A = ŌłÜ3/4 a2 =  ŌłÜ3/4 ├Ś 10 ├Ś 10 = 25ŌłÜ3 cm2

4. The lateral surface area of a cube of side 12 cm is

(1) 144 cm2

(2) 196 cm2

(3) 576 cm2

(4) 664 cm2

Solution:

4a2 = 4├Ś12├Ś12 = 4├Ś144=576 cm2

5. If the lateral surface area of a cube is 600 cm2, then the total surface area is

(1) 150 cm2

(2) 400 cm2

(3) 900 cm2

(4) 1350 cm2

Solution:

4a2 =600 cm2

6a2 = [6 ├Ś 600 ] /4

6a2 = 900

6. The total surface area of a cuboid with dimension 10 cm ├Ś 6 cm ├Ś 5 cm is

(1) 280 cm2

(2) 300 cm2

(3) 360 cm2

(4) 600 cm2

Solution:

TSA = 2 (lb + bh + hl)

= 2 (10 ├Ś 6 + 6 ├Ś 5 + 5 ├Ś 10) = 2 (60 + 30 + 50) = 2 (140) = 280 cm2

7. If the ratio of the sides of two cubes are 2:3, then ratio of their surface areas will be

(1) 4:6

(2) 4:9

(3) 6:9

(4) 16:36

Solution:

a:b = 2:3

4a2:4b2 = 4├Ś22:4├Ś32

16:36

4:9

8. The volume of a cuboid is 660 cm3 and the area of the base is 33 cm2. Its height is

(1) 10 cm

(2) 12 cm

(3) 20 cm

(4) 22 cm

Solution:

V = 660 cm3

lb = 33 cm2

h = ?

lbh = 660

h = 660 /33 = 20

9. The capacity of a water tank of dimensions 10 m ├Ś 5 m ├Ś 1.5 m is

(1) 75 litres

(2) 750 litres

(3) 7500 litres

(4) 75000 litres

Solution:

Volume of cuboid = l ├Ś b ├Ś h

10. The number of bricks each measuring 50 cm ├Ś 30 cm ├Ś 20 cm that will be required to build a wall whose dimensions are 5 m ├Ś 3 m ├Ś 2 m is

(1) 1000

(2) 2000

(3) 3000

(4) 5000

Solution:

500├Ś300├Ś200 / 50├Ś30├Ś20 = 1000