octagon
An octagon is a polygon with eight vertices and eight sides.
There are two types of octagon:
(1) Regular octagon
(2) Irregular octagon.
Regular octagons and irregular octagons have eight sides, and the interior angles of both add up to a total of 1080°. The interior angles of a regular octagon are always 135°, 1080° ÷ 8 = 135°. The interior angles of an irregular octagon are not all equal.