Question

Total surface area of a cylinder of radius r and height h is

• A. $2\pi r^2+4\pi rh$
• B. $2\pi r^2+2\pi rh$
• C. $2\pi rh$

Answer 1

The correct option is B $2\pi r^2+2\pi rh$

A cylinder has two circular flat surfaces and a curved surface.

As $r$ is the radius of the cylinder the area of a flat surface is
$\pi r^2.$ Therefore, the area of two flat surfaces is
$2\times \pi r^2=2\pi r^2.$

The area of the curved surface is $=2\pi r\times h=2\pi rh$
as the height of the cylinder is $h$.

Hence, the total surface area the cylinder is $=2\pi r^2+2\pi rh$.