Question

Find the area of base and radius of a cylinder if its curved surface area is 660 sqcm and height is 21 cm.

Answer 1

Given, Curves surface area = 660 sq cm
And, height = 21 cm

Curved surface area of a cylinder = $2\pi rh$

Area of base of cylinder = $\pi r^2$

Where $r$ is the radius and $h$ is the height of cylinder.

Now, by curved surface area of cylinder,

$\Rightarrow 2\pi rh=660$

$\Rightarrow 2\times \frac{22}{7}\times r\times 3=660$

$\Rightarrow 660=132r$

$\Rightarrow r=\frac{660}{132}$

$\Rightarrow r=5cm$

Again, by area of base of cylinder,

$=\pi r^2$

$=\frac{22}{7}\times 5^2$

$=78.6{cm}^2$

Hence, the area of base and radius of a cylinder is

$78.6{cm}^2$

and

$5cm$

respectively.