Question:
The diameter of the base of a right circular cylinder is 42 cm and its height is 10 cm. Find the volume of the cylinder.
Solution:
Given :
Diameter, $d=42 \mathrm{~cm}$
Radius, $r=\frac{d}{2}=21 \mathrm{~cm}$
Height, $h=10 \mathrm{~cm}$
Volume of the cylinder, $\mathrm{V}=\pi r^{2} h$
$=\frac{22}{7} \times 21^{2} \times 10$
$=13860 \mathrm{~cm}^{3}$