Question

The curved surface area of a cylinder is $1320c{m}^2$ and its base has diameter 21 cm. Find the volume of the cylinder.

Answer 1

Given: Diameter of base of cylinder = 21 cm

$\Rightarrow$ Radius of base of cylinder (𝑟) $=\frac{d}{2}=\frac{21}{2}cm$

Also, curved surface area of cylinder $=1320c{m}^2$
$\Rightarrow 2\pi rh=1320$
$\Rightarrow 2\times \frac{22}{7}\times \frac{21}{2}\times h=1320$
$\Rightarrow h=\frac{1320\times 7\times 2}{2\times 22\times 21}$
$=\frac{18480}{924}$
= 20 cm

$\therefore$ Volume of cylinder $=\pi r^{2}h$
$=\frac{22}{7}\times \frac{21}{2}\times \frac{21}{2}\times 20$
$=6930c{m}^3$

Hence, the volume of the cylinder is $6930c{m}^3$