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

** [Answer: (3) 30 cm]**

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

(1) 3 *cm*^{2}

**(2) 6 cm^{2}**

(3) 9 *cm*^{2}

(4) 12 *cm*^{2}

**Solution:**

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

A = âˆš[6(6 âˆ’ 3)(6 âˆ’ 4)(6 âˆ’ 5)] = âˆš[6 Ã— 3 Ã— 2 Ã— 1] = âˆš36 = 6 *sq. cm** *

**[Answer: (2) 6 cm^{2}]**

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

(1) 10âˆš3
*cm*^{2}

(2) 12âˆš3
*cm*^{2}

(3) 15âˆš3
*cm*^{2}

**(4) 25âˆš3 cm^{2}**

**Solution:**

3*a*=30

*a *= 10 *cm*

A = âˆš3/4 *a*^{2} = âˆš3/4 Ã— 10 Ã— 10 = 25âˆš3 *cm*^{2}_{}

**[Answer: (4) 25âˆš3 cm^{2}]**

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

(1) 144 *cm*^{2}

(2) 196 *cm*^{2}

**(3) 576 cm^{2}**

(4) 664 *cm*^{2}

**Solution:**

4*a*^{2} = 4Ã—12Ã—12 = 4Ã—144=576 *cm*^{2}

**[Answer: (3) 576 cm^{2}]**

5. If the
lateral surface area of a cube is 600 *cm*^{2}, then the total surface
area is

(1) 150 *cm*^{2}

(2) 400 *cm*^{2}

**(3) 900 cm^{2}**

(4) 1350
*cm*^{2}

**Solution:**

4*a*^{2} =600 cm^{2}

6*a*^{2} = [6 Ã— 600 ] /4

6*a*^{2} = 900

**[Answer: (3) 900 cm^{2}]**

6. The total
surface area of a cuboid with dimension 10 *cm Ã—* 6 *cm Ã—* 5 *cm*
is

**(1) 280 cm^{2} **

(2) 300 *cm*^{2}

(3) 360 *cm*^{2}

(4) 600 *cm*^{2}

**Solution:**

TSA = 2 (*lb + bh + hl*)

= 2 (10 Ã— 6 + 6 Ã— 5 + 5 Ã— 10) = 2 (60 + 30 + 50) = 2 (140) = 280 *cm*^{2}

**[Answer: (1) 280 cm^{2}]**

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

4*a*^{2}:4*b*^{2}
= 4Ã—2^{2}:4Ã—3^{2}

16:36

4:9

**[Answer: (2) 4:9]**

8. The
volume of a cuboid is 660 *cm*^{3} and the area of the base is 33 *cm*^{2}.
Its height is

(1) 10 *cm*

(2) 12 *cm*

**(3) 20 cm**

(4) 22 *cm*

**Solution:**

V = 660 cm^{3}

*lb* = 33 cm^{2}

*h* = ?

*lbh* = 660

*h* = 660 /33 = 20

**[Answer: (3) 20 cm]**

9. The
capacity of a water tank of dimensions 10 *m Ã—* 5 *m Ã—* 1.5 *m* is

(1) 75 litres

(2) 750 litres

**(3) 7500 litres**** **

(4) 75000 litres

**Solution:**

Volume of cuboid = *l **Ã—** b **Ã—** h** *

**[Answer: (3) 7500 litres]**

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

**(1) 1000**** **

(2) 2000

(3) 3000

(4) 5000

**Solution:**

500Ã—300Ã—200 / 50Ã—30Ã—20 = 1000

**[Answer: (1) 1000]**

Tags : Numerical Problems with Answers, Solution | Mensuration | Maths , 9th Maths : UNIT 7 : Mensuration

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9th Maths : UNIT 7 : Mensuration : Exercise 7.4: Multiple choice questions | Numerical Problems with Answers, Solution | Mensuration | Maths

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