Question:
The surface area of a sphere is same as the curved surface area of a right circular cylinder whose height and diameter are 12 cm each. The radius of the sphere is
(a) 3 cm
(b) 4 cm
(c) 6 cm
(d) 12 cm
Solution:
Let r be the radius of sphere
But,
Surface area of sphere = C.S.A. of cylinder
$r=6 \mathrm{~cm}$
Hence, the correct answer is choice (c).