Find the total surface area of a hemisphere of radius 10 cm. (Use = 3.14)
r = 10 cm.
∴ Total surface area of the hemisphere = 3πr2
= 3 x 3.14 x (10)2 = 942 cm2.
A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin-plating it on the inside at the rate of ` 16 per 100 cm2.
A right circular cylinder just encloses a sphere of radius r. Find
(i) surface area of the sphere,
(ii) curved surface area of the cylinder,
(iii) ratio of the areas obtained in (i) and (ii).