Octadecagon
A octadecagon or 18-gon is a shape with 18 sides and 18 corners.
Regular octadecagon
All sides of a regular octadecagon are the same length. Each corner is 160°. All corners added together equal 2880°.
Area
The amount of space a regular octadecagon takes up is
The area of a regular octadecagon of side length a is given by
- [math]\displaystyle{ A = \frac{18}{4}a^2\cot\frac{\pi}{18}\simeq 25,5208a^2 }[/math]