Question

The slant height and base diameter of a conical tomb are 25 m and 14 m respectively. Find the cost of whitewashing its curved surface at the rate of ₹210 per 100 m2.

Answer 1

Slant height (l) of conical tomb = 25 m
Base radius (r) of tomb = $\frac{14}{2}$=7 m
CSA of conical tomb = $\pi rl$
= $\frac{22}{7}$ × 7 m × 25 m
= 550m2
Cost of white-washing 100 m2 area = Rs 210
Cost of white-washing 550 m2 area = ($\frac{210}{100}$) × 550
= ₹1155
Therefore, it will cost Rs 1155 while whitewashing such a conical tomb.