Question

The diameter of a solid hemisphere is 42 cm. Find its volume, curved surface area and total surface area.

Answer 1

Given :

Diameter of hemisphere $=42cm$

$\therefore$Radius $\left(r\right)=21$ $cm$

We know that,

Volume of a hemisphere $=\frac{2}{3}\pi r^3$

$\therefore \frac{2}{3}\times \frac{22}{7}\times 21\times 21\times 21$ [using $\pi =\frac{22}{7}$]

$=19404$ $c{m}^3$

We know that,

Curved surface area of a hemisphere $=2\pi r^2$

$\therefore 2\times \frac{22}{7}\times 21\times 21$

$=2772$ $c{m}^2$

We also know that,

Total surface area of a hemisphere $=3\pi r^2$

$\therefore 3\times \frac{22}{7}\times 21\times 21$

$=4158$ $c{m}^2$

Hence, the volume, curved surface area and total surface area of the given hemisphere are $19404c{m}^3,2772c{m}^2\text{and}4158c{m}^2$, respectively.