Question

The area of the base of a right circular cylinder is $81\pi$. If its height is $14cm$, find the curved surface of the cylinder.

Answer 1

Let the radius of the base be $rcm$

Area of base of the cylinder = $81\pi$

We know, Area of base = $\pi r^2$

$\Rightarrow \pi r^2=81\pi$

$\Rightarrow r^2=81$

$\Rightarrow r=9$

Height = $14cm$

CSA of cylinder $=2\pi rh$

$=2\times \pi \times 9\times 14$

$=2\times \frac{22}{7}\times 9\times 14c{m}^2$

$=22\times 36c{m}^2=792c{m}^2$