Pentagons, hexagons and more

Pentagons

Polygons with five sides and five internal angles are called pentagons. A regular pentagon is seen below. All five sides and internal angles are equal.

The pentagon seen below is an irregular pentagon. All the sides and internal angles are not equal.

Hexagons

A polygon with six sides and six internal angles is called a hexagon. Look at the hexagon below. Do you think it is a regular hexagon? Why do you think so?

Do you think the hexagon seen below is a regular hexagon? Why do you think so?

Heptagons

Polygons with seven sides and seven internal angles are called heptagons. The heptagon seen below is a regular heptagon because all its sides and internal angles are equal.

Regular heptagon (Image by WikiMakersOfOurTime and used under this creative commons license)

An irregular heptagon is seen in the picture below. Why is it called an irregular heptagon?

Image by Kilom691 and used under this creative commons license.

Octagons

Octagons are polygons with eight sides and eight internal angles. One regular and one irregular octagon are shown below.

Nonagons

Polygons with 9 sides and nine internal angles are called nonagons. One regular and one irregular nonagon can be seen below.

This is a regular nonagon. Image by Person Unknown and used under this creative commons license.

Decagons

Polygons with ten sides and ten internal angles are called decagons. A regular and an irregular decagon can be seen below.