Convex and Concave Octagon

Based on their interior angles, all octagons are classified into two groups: convex and concave.

What is a Convex Octagon

A convex octagon is an octagon having each interior angle less than 180°. Each of the vertices of a convex octagon always points outwards. All the diagonals of such an octagon lie inside the closed figure. It can be regular or irregular.

What is a Concave Octagon

A concave octagon, also called a non-convex octagon, is an octagon that has at least one interior angle greater than 180°. At least one vertex of a concave octagon points inwards. It will always be an irregular octagon.