A polygon is simply a closed shape with straight lines. Triangles, squares and hexagons are all polygons. Within polygons there are two main types. Irregular polygons and regular polygons. A regular polygon is just a polygon where all the sides and all the angles are equal. These are shapes like equilateral triangles, and squares.


Irregular polygons are simply shapes where at least one side or angle is unequal.

Lessons:

Quadrilaterals
Regular and Irregular Polygons
Types of Triangles