Question

What is the formula for a cylinder and a circle?

Answer 1

The surface area of a right cylinder equals $2 \pi rh+2 \pi r^2$

As you can see in the attached picture, the surface area consists of two equal circles (bottom and top one) and area that would look like a rectangle, if "unraveled".

The formulae for the surface area of the circle is $\pi r^{2}$. You have to multiply it by two and add to the area of the "rectangle", which equals $2 \pi rh$ where $2 \pi r$ is the circumference of the circle and $h$ is the height of the cylinder.