Pentagon

In geometry, a pentagon (from pente, which is Greek for the number 5) is any five-sided polygon. A pentagon may be simple or self-intersecting. The sum of the internal angles in a simple pentagon is 540°. A pentagram is an example of a self-intersecting pentagon.

Read more about Pentagon:  Regular Pentagons, Construction of A Regular Pentagon, Cyclic Pentagons, Graphs, Pentagons in Tiling