Polygon

A closed plane figure for which all sides are line segments. The name of a polygon describes the number of sides. A polygon which has all sides mutually congruent and all angles mutually congruent is called a regular polygon.

Number of sides	Polygon name	pentagon regular undecagon octagon
3	triangle
4	quadrilateral
5	pentagon
6	hexagon
7	heptagon
8	octagon
9	nonagon
10	decagon
11	undecagon
12	dodecagon
n	n-gon

See also

Area of a regular polygon, area of a convex polygon

Polygons

·         Polygons – are closed figures formed by joining three or more line segments.

Kinds of Polygons

1. Equilateral polygon – a polygon whose sides are of the same length.

2. Equiangular polygon – a polygon whose angles are all equal.

3. Regular polygon – a polygon which is both equilateral and equiangular.

4. Congruent figure – a figure like a line or polygon with the same size and shape. Angles with the same measure are congruent.   

Octagon – a two dimensional geometric figure formed of eight

sides and eight angles.

Icosahedron – a three dimensional geometric figure formed of 20 sides or faces.