A hemi-spherical dome of a building needs to be painted. IF the circumference of the base of the dome is 17.6 m, find the cost of painting it, given the cost of painting is Rs. 5 per 100 cm2.

Circumference of a circle = 2πr


Surface area of a hemisphere = 2πr2


Given, base of the dome is 17.16 m


2 × (22/7) × r = 17.6


r = 2.8 m


Surface area of the hemisphere = 2 × (22/7) × 2.82 = 49.28 m2 = 492800 cm2


Cost of painting is Rs. 5 per 100 cm2,


Cost of painting the dome = (492800/100) × 5 = Rs. 24640


12