Question:
The curved surface area of a cylinder is $1320 \mathrm{~cm}^{2}$ and its base had diameter $21 \mathrm{~cm}$. Find the height and volume of the cylinder.
Solution:
Let, r be the radius of the cylinder
h be the height of the cylinder
⟹ 2r = 21cm
⟹ r = 21/2
= 10.5 cm
Given, Curved surface area (CSA) $=1320 \mathrm{~cm}^{2}$
⟹ 2πrh = 1320
⟹ 2 * 22/7 * 10.5 * h = 1320
⟹ h = 1320/66
⟹ h = 20 cm
Volume of cylinder $=\pi r^{2} * \mathrm{~h}$
= 22/7 * 10.5 * 10.5 * 20
= 22 * 1.5 * 10.5 * 20
$=6930 \mathrm{~cm}^{2}$