Question

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

Answer 1

Let the slant height of the cone be 'l' meters.
height = 24 m and diameter = 14 m or radius = 7 m.
Then according to the question.
l² = h² + r²
l² = 24² + 7²
l² = 576 + 49
l² = 625
l = √625
l = 25 m
So, the slant height of the cone is 25 m.
Now,
Curved Surface Area of the cone = πrl
= $\frac{22}{7}$$\times$ 7$\times$25
CSA = 550 sq m
Now, length of the cloth used = $\frac{Area}{widthofthecloth}$
=$\frac{550}{5}$
Length of the cloth used = 110 m
Cost of cloth = Rs. 25 per meter
Total cost of clothe used = 110$\times$25