Question

A cone of the radius is 7 m and the height is 24 m. It was formed by cloth of width 5 m. Find how much metre cloth required?
1. 110 m
2. 120 m
3. 150 m
4. 180 m

Answer 1

Correct Answer - Option 1 : 110 m

Given:

Radius of cone = 7 m

Height of the cone = 24 m

Width of cloth = 5 m

Formula used:

The lateral surface area of cone = πrl

l² = r² + h²

Area of rectangle = L × B

Where,

r = radius of cone

l = slant height of the cone

h = height of the cone

L = length of rectangle

B = Breadth of rectangle

Calculation:

l² = r² + h²

⇒ l² = 7² + 24²

⇒ l = 25 m

The lateral surface area of cone = Area of the cloth

⇒ πrl = L × B

⇒ (22/7) × 7 × 25 = L × 5

⇒ L = 110 m

∴ Length of cloth required is 110 m.