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.