Question

A 5-m-wide cloth is used to make a conical tent of base diameter 14 m and height 24 m. Find the cost of cloth used at the rate of Rs.25 per metre.

Answer 1

Given:

Width of cloth used = 5 m

Diameter of conical tent = 14 m

Let r be the radius of the conical tent.

Diameter of conical tent = 14 m

Radius = r = 14/2 m = 7 m

Height = h = 24 m

Let slant height of conical tent = l m

So , 

l = 25 m

Curved Surface area of conical tent = πrl

= 22/7 × 7 × 25 m²

= 550 m²

Which is the area of cloth required to make a conical tent that is 550 m²

Now,

Area of cloth required = Length of cloth used x width of cloth

or

Length of cloth used = Area of cloth required ÷ width of cloth

= 550/5 m

= 110 m

Length of cloth used = 110 m

Given, Cost of cloth used = Rs 25 per meter

Total Cost of cloth required to make a conical tent = 110 × Rs 25

= Rs 2750