# Heptagon

## Heptagon

Polygon with seven sides.
Each of the interior angles of a regular heptagon measures approximately 128.6°.

### Formula

The formula to calculate the area A of a regular heptagon of side length c is:

$$A=\frac{7c^{2}}{4}\mathrm{cot}(\frac{\pi}{7} )$$

### Examples

• This heptagon, which is inscribed in a circle, is a regular heptagon:

• This heptagon is not a regular heptagon.