A list of regular polygons and their names. Polygons are figures composed of a number of straight lines that are joined together. Regular polygons have equal length sides and equal interior angles. Polygons are named according to their number of sides.
Often polygons with sides numbering greater then 10 are simply referred to n-gon (e.g. 17-gon) for convenience
No. of sides |
Polygon Name | Internal Angle |
---|---|---|
3 | Triangle | 60° |
4 | Square or Quadrilateral | 90° |
5 | Pentagon | 108° |
6 | Hexagon | 120° |
7 | Heptagon | 128.571° |
8 | Octagon | 135° |
9 | Nonagon or Ennagon | 140° |
10 | Decagon | 144° |
11 | Hendecagon or Undecagon | 147.273° |
12 | Dodecagon | 150° |
13 | Triskaidecagon | 152.308° |
14 | Tetrakaidecagon | 154.286° |
15 | Pendedecagon | 156° |
16 | Hexdecagon | 157.5° |
17 | Heptdecagon | 158.824° |
18 | Octdecagon | 160° |
19 | Enneadecagon | 161.053° |
20 | Icosagon | 162° |
30 | Triacontagon | 168° |
40 | Tetracontagon | 171° |
50 | Pentacontagon | 172.8° |
60 | Hexacontagon | 174° |
70 | Heptacontagon | 174.857° |
80 | Octacontagon | 175.5° |
90 | Enneacontagon | 176° |
100 | Hectagon | 176.4° |
1000 | Chiliagon | 179.640° |
10000 | Myriagon | 179.964° |
100000 | Megagon | 179.996° |
10100 | Googolgon | almost 180° :-) |
Polygons with sides numbering between the main divisions of ten above are named by combining the prefixes and suffixes listed below. For example a 56 sided polygon would be called a Pentacontakaihexagon.
No. of Sides |
Name Prefix | Name Suffix | No. of Sides |
|
---|---|---|---|---|
20 | Icosikai... | combine with | ...henagon | 1 |
30 | Triacontakai... | ...digon | 2 | |
40 | Tetracontakai... | ...trigon | 3 | |
50 | Pentacontakai... | ...tetragon | 4 | |
60 | Hexacontakai... | ...pentagon | 5 | |
70 | Heptacontakai... | ...hexagon | 6 | |
80 | Octacontakai... | ...heptagon | 7 | |
90 | Enneacontakai... | ...octagon | 8 | |
...enneagon | 9 |