Question

A sphere, cylinder & a cone gave the same radius & same height, find the ratio of their curved surface areas.

Answer 1

C.S.A of sphere$=4\pi r^2$

C.S.A of cylinder$=2\pi rh$

C.S.A of cone$=\pi rl$$=\pi r\sqrt{h^2+r^2}$

Ratio$=4\pi r^2:2\pi rh:\pi r\sqrt{h^2+r^2}$

$=4r:2h:\sqrt{h^2+r^2}$.