Question

Curved surface area of a cylinder is 1980 cm² and radius of its base is 15 cm. Find the height of the cylinder. ($\mathrm{\pi }=\frac{22}{7}$).

Answer 1

Let the height of the cylinder be h cm.

Radius of the cylinder, r = 15 cm

Curved surface area of the cylinder = 1980 cm²

∴ 2$\mathrm{\pi }$rh = 1980 cm²

$$\begin{gathered} \Rightarrow 2\times \frac{22}{7}\times 15\times h=1980 \\ \Rightarrow h=\frac{1980\times 7}{660}=21\mathrm{cm} \end{gathered}$$
Thus, the height of the cylinder is 21 cm.