3. There are names for polygons all the way up to 20 sides and for all 10's up to 100 sides, but in general if a polygon has 19 sides, for example, we call it a 19-gon and so on. Here are the names for polygons up to 12 sides.

Sides Prefix Name
3 tri- triangle
4 quad- quadrilateral
5 penta- pentagon
6 hexa- hexagon
7 hepta- heptagon
8 octa- octagon
9 nona- nonagon
10 deca- decagon
11 undeca- undecagon
12 dodeca- dodecagon

Below are some examples of these polygons.

Quadrilaterals are all around us, in everything from fabrics to buildings. Rectangles are very common. The four angles of a rectangle are all 90° and fit together well; lumber stacks into neat piles and rooms fit into rectangular buildings:

Pentagons are less commonly found than quadrilaterals. If you drew a polygon that just fit around this Plumeria flower (below), the polygon would be a pentagon. In Hawaii, we call this flower a Plumeria, and in Tahiti it is called Frangipani.

A polygon with six sides is called a hexagon. We often see hexagons in signs, fabric, even furniture. Every snowflake is a hexagon, and every one is different.

The hexagon is sometimes used to create the illusion of a cube by connecting every other vertex to the centre, forming three diamonds, and shading each diamond differently.

A heptagon is a seven-sided figure and is very rare. Can you find one?

Octagons are much more common, with their eight sides. Designers and artists use octagons in their work.

There are many polygons, some regular and many irregular... you see them every day, perhaps without noticing them.