Question

A vessel is in the form of a hollow hemisphere mounted by a hollow cylinder. The radius of the hemisphere is 7 cm and the total height of the vessel is 13 cm. Find the inner surface area of the vessel.

Answer 1

Given:

Radius of hemisphere and cylinder is $r=7cm$

Height of cylinder is $h=13cm$

Surface area of hemisphere of radius $r$ is given by $S_1=2\pi r^2$

Surface area of curved surface of a cylinder of radius $r$ and height $h$ is $S_2=2\pi rh$

Total surface area is $S=2\pi r^2+2\pi rh$

$S=2\pi \times 7^2+2\pi \times 7\times 13$

$S=280\pi c{m}^2$