- A polygon can also be defined as a closed polygonal chain.
- The point where two sides meet is the vertex of the polygon.
- Each line segment that joins two vertices is a side of the polygon.

The polygons listed below are named according to their number of sides:

- 3 sides: triangle
- 4 sides: quadrilateral
- 5 sides: pentagon
- 6 sides: hexagon
- 7 sides: heptagon
- 8 sides: octagon
- 9 sides: nonagon
- 10 sides: decagon
- 11 sides: hendecagon
- 12 sides: dodecagon
- 15 sides: pentadecagon
- 16 sides: hexadecagon
- 20 sides: icosagon
- 30 sides: triacontagon
- 50 sides: pentacontagon
- 100 sides: hectagon
- 1000 sides: chiliagon
- 10 000 sides: myriagon

### Examples

This polygon has 4 vertices and 4 sides :

The closed polygonal chains below form various types of polygons: