How many litres of milk can a hemispherical bowl of diameter 10.5 cm hold?

A hemispherical tank is made up of an iron sheet 1 cm thick. If the inner radius is 1 m, then find the volume of the iron used to make the tank.

A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of ₹ 4989.60. If the cost of white-washing is ₹ 20 per square metre, find the

(i) inside surface area of the dome,

(ii) volume of the air inside the dome.

Twenty seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area S′. Find the

(i) radius r′ of the new sphere,

(ii) ratio of S and S′.