A semi-circular lamina of radius 35 cm is folded so that the two bounding radii are joined together to form a cone. Find :

(i) the radius of the cone.

(ii) the (lateral) surface area of the cone.

Find the surface area and volume of a sphere of radius 14 cm.

A shot-put is a metallic sphere of radius 4.9 cm. If the density of the metal is 7.8 g per cm³, find the mass of the shot-put.

Find the diameter of a sphere whose surface area is 154 cm².