Mathematics
The radius of a spherical balloon increases from 7 cm to 14 cm as air is pumped into it. Find the ratio of the surface areas of the balloon in two cases.
Related Questions
Find
(i) the curved surface area.
(ii) the total surface area of a hemisphere of radius 21 cm.
A hemispherical brass bowl has inner-diameter 10.5 cm. Find the cost of tin-plating it on the inside at the rate of ₹ 16 per 100 cm2.
If the ratio of the radii of two spheres is 3 : 7, find :
(i) the ratio of their volumes.
(ii) the ratio of their surface areas.