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# What are the names given to regular polygons?

Polygons are classified according to the number of sides they have. A polygon with n sides is called an n-gon. The following lists some of the names of polygons, depending on the number of sides. It is also possible to substitute “n-gon,” when the name is not known (for example 14-gon or 20-gon).

 Sides Polygon Name 3 trigon or triangle 4 quadrilateral or tetragon 5 pentagon 6 hexagon 7 heptagon 8 octagon 9 nonagon or enneagon 10 decagon 11 hendecagon or undecagon (even less frequently as unidecagon) 12 dodecagon 13 tridecagon or triskaidecagon 14 tetradecagon or tetrakaidecagon 15 pentadecagon or pentakaidecagon 16 hexadecagon or hexakaidecagon 17 heptadecagon or heptakaidecagon 18 octadecagon or octakaidecagon 19 enneadecagon or enneakaidecagon 20 icosagon 30 triacontagon 40 tetracontagon 50 pentacontagon 60 hexacontagon 70 heptacontagon 80 octacontagon 90 enneacontagon 100 hectogon or hecatontagon 1,000 chiliagon 10,000 myriagon

Some texts list a two-sided polygon as a “digon,” but this is only meant for theoretical mathematics. If you feel like making up your own name, try constructing some sided polygons. For example, a 46-sided polygon could be called a tetracontakai-hexagon, or a combination of “tetracon-tagon” + “kai” (often used in combining names) + “hexagon.” To shorten such long names, mathematicians often use “n-gon” to simplify matters; thus, 46 would be 46-gon a much easier name to remember and even say.

The parts of a polygon.

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