Question

If the total surface area of a solid hemisphere is $462c{m}^2$, find its volume.

Answer 1

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

$3\pi r^2=462$

$3\times \frac{22}{7}\times r^2=462$

$\frac{66}{7}\times r^2=462$

$r^2=49$

$r=\sqrt{49}$

r=7.

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

$=\frac{2}{3}\times \frac{22}{7}\times 7\times 7\times 7$

=718.6cm${}^3.$