Regular polygons


Martin McBride, 2020-08-14
Tags regular polygon equilateral triangle square pentagon hexagon octagon
Categories maths gcse geometry

A regular polygon is a polygon for which every side is equal and every angle is equal. In this section we will look at some well known regular polygons with 3 to 12 sides. Here is a video:

3 sides - equilateral triangle

A three sided shape, of course, is called a triangle. A regular triangle is called an equilateral triangle, and looks like this:

4 sides - square

A four sided shape is called a quadrilateral. A regular quadrilaterals are more commonly known as squares:

5 sides - pentagon

A five sided shape is called a pentagon. A regular pentagon looks like this:

6 sides - hexagon

A six sided shape is called a hexagon. A regular hexagon looks like this:

7 sides - heptagon

A seven sided shape is called a heptagon. A regular heptagon looks like this:

8 sides - octagon

A eight sided shape is called an octagon. A regular octagon looks like this:

9 sides - nonagon

A nine sided shape is called a nonagon. A regular nonagon looks like this:

10 sides - decagon

A ten sided shape is called a decagon. A regular decagon looks like this:

11 sides - hendecagon

An eleven sided shape is called a hendecagon. A regular hendecagon looks like this:

12 sides - dodecagon

A twelve sided shape is called a dodecagon. A regular dodecagon looks like this:

Polygons with more sides

A polygon can have any number of sides, but most do not have well known special names.

Irregular polygons

An irregular polygon is a polygon where some of the sides and/or angles are different. Some irregular triangles and quadrilaterals have special names (isosceles triangle, rectangle, parallelogram, etc), but irregular shapes with more than four side usually don't.

Copyright (c) Axlesoft Ltd 2020