Polygons

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Polygons

A polygon is closed plane figure formed by the joining of three or more straight lines. A regular polygon is one that has equal sides and equal interior angles.

Regular Polygons
Sides Name Interior Angles Exterior Angles
3 Triangle 60.00° 120.00°
4 Quadrilateral 90.00° 90.00°
5 Pentagon 108.00° 72.00°
6 Hexagon 120.00° 60.00°
7 Heptagon 128.57° 51.43°
8 Octagon 135.00° 45.00°
9 Nonagon 140.00° 40.00°
10 Decagon 144.00° 36.00°
11 Hendecagon 147.27° 32.73°
12 Dodecagon 150.00° 30.00°
13 Triskaidecagon 152.31° 27.69°
14 Tetrakaidecagon 154.29° 25.71°
15 Pendedecagon 156.00° 24.00°
16 Hexdecagon 157.50° 22.50°
17 Heptdecagon 158.82° 21.18°
18 Octdecagon 160.00° 20.00°
19 Enneadecagon 161.05° 18.95°
20 Icosagon 162.00° 18.00°
30 Triacontagon 168.00° 12.00°
40 Tetracontagon 171.00° 9.00°
50 Pentacontagon 172.80° 7.20°
60 Hexacontagon 174.00° 6.00°
70 Heptacontagon 174.86° 5.14°
80 Octacontagon 175.50° 4.50°
90 Enneacontagon 176.00° 4.00°
100 Hectogon 176.40° 3.60°
1,000 Chiliagon 179.64° 0.36°
10,000 Myriagon 179.96° 0.04°

Note: After about 6 sides mathematicians usually refer to these polygons as n-gons, so a 23 sided polygon would be called a 23-gon.

The sum of the measures of the angles of a convex polygon with n sides is (n - 2)180.

Polygon Angle Calculator
Sides of polygon:
Each exterior angle:
Each interior angle:

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