Question

If the lateral surface of a cylinder is $94.2$ ${\text{cm}}^2$ and its height is $5$ cm, then find

(i) radius of its base

(ii) its volume.(Use $\pi$ $=3.14$)

Answer 1

Let the radius of cylinder is $r\text{cm}$

Given:

Height $=5\text{cm}$

Lateral or curved surface area $=94.2{\text{cm}}^2$

(i)

$\because$ Curved surface area of the cylinder of radius $r$ and height $h$ is $2\pi rh$

$⟹2\pi rh=94.2$

$⟹2\pi r\times 5=94.2$

$⟹r=\frac{94.2}{2\times 3.14\times 5}$

$⟹r=3\text{cm}$

(ii)

Volume of a cylinder of radius $r$ and height $h$ is $\pi r^{2}h$

$⟹$ Volume $=3.14\times 3\times 3\times 5$

$⟹$Volume $=141.3{\text{cm}}^3$