Question

The area of one end of a cylinder is $154{cm}^2$ and its height is $21cm$. Find the volume and curved surface area of cylinder.

Answer 1

Given Height of cylinder $\left(h\right)=21cm$
Area of its one end $=154{cm}^2$
$\pi r^2=154$
$\Rightarrow \frac{22}{7}\times r^2=154$
$r^2=\frac{154\times 7}{22}$
$=\frac{1078}{22}=49$
$r=\sqrt{49}=\sqrt{7\times 7}$
$r=7cm$
Volume of cylinder $=\pi r^{2}h$ $=\frac{22}{7}\times 7\times 7\times 21$
$=22\times 7\times 21$
$=3234{cm}^3$
Curved surface area $=2\pi rh=2\times \frac{22}{7}\times 7\times 21$
$=2\times 22\times 21$
$=924{cm}^2$
Hence, the volume of cylinder $=3234{cm}^3$
Curve surface area $=924{cm}^2$