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.