Polygon Calculator
Calculate the various properties of Area of Polygon for given values.
Formulas
Area of Polygon
(Using length of a side)
[ ((side)²×N)/(4tan(π/N)) ]
Area of Polygon
Using radius (circumradius)
[ ½×R²×sin(2π/N) ]
Area of Polygon
[Using apothem (inradius)] :
[ A²×N×tan(π/N) ]
[ Apothem(A) = R×cos(π/N) ]
Area of Polygon
[Using apothem and length of a side]
[ (A×P)/2 ]
[ Apothem(A) : side/(2×tan(π/N)) ]
Perimeter of Polygon:
[ N×(side) ]
Important Links 
Type of polygons with definition and shape :
Polygons Type  Definition  Shape 
Regular polygons  The polygon having all sides and interior angles of the same size.  
Irregular polygons  Every side and angle may be of different size.  
Convex polygons  Every interior angles are < 180° and every vertices "point outwards" away from the interior. The regular polygons are always convex.  
Concave polygons  One or more interior angles > 180° and some vertices push "inwards" towards the interior of the polygon.  
Crossed polygons  The The polygon where any or more sides are crossing back over another side means forming multiple smaller polygons.  
Polygon has >= 10 sides  Can be written as: 11gon, 12gon, 13gon, 14gon, 20gon ... "100gon", etc. 
Name of polygons, Number of sides and angles
Polygon  Name  n (sides)  ∠A  ∠B 

11  sided polygon  Hendecagon (undecagon)  11  147.273°  32.73° 
12  sided polygon  Dodecagon  12  150°  30° 
13  sided polygon  Triskaidecagon  13  152.308°  27.69° 
14  sided polygon  Tetrakaidecagon  14  154.286°  25.71° 
15  sided polygon  Pentadecagon  15  156°

24° 
16  sided polygon  Hexakaidecagon  16  157.5°

22.5° 
17  sided polygon  Heptadecagon  17  158.824°

21.18° 
18  sided polygon  Octakaidecagon  18  160°

20° 
19  sided polygon  Enneadecagon  19  161.053°

18.98° 
20  sided polygon  Icosagon  20  162°

18° 
30  sided polygon  Triacontagon  30  168°

12° 
40  sided polygon  Tetracontagon  40  171°

9° 
50  sided polygon  Pentacontagon  50  172.8°

7.2° 
60  sided polygon  Hexacontagon  60  174°

6° 
70  sided polygon  Heptacontagon  70  174.857°

5.14° 
80  sided polygon  Octacontagon  80  175.5°

4.5° 
90  sided polygon  Enneacontagon  90  176°

4° 
100  sided polygon  Hectagon  100  176.4°

3.6° 
1,000  sided polygon  Chiliagon  1,000  179.64°

0.36° 
10,000  sided polygon  Myriagon  10,000  179.964°

0.036° 
1,000,000  sided polygon  Megagon  1,000,000  ~180°  ~0° 
10^{100}  sided polygon  Googolgon  10^{100}  ~180°  ~0° 