Question

The dome of a building is in the form of a hemisphere. Its radius is 63 dm. Find the cost of painting it at the rate of Rs. 2 per sq m.

Answer 1

Radius of hemispherical dome = 63 dm or 6.3 m 

Inner surface area of dome = 2πr² 

= 2 x 3.14 x (6.3)² 

= 249.48 

So, Inner surface area of dome is 249.48 m² 

Cost of painting 1m² = Rs.2

Therefore, cost of painting 249.48 m² = Rs. (249.48 x 2) 

= Rs.498.96.