Rather than using the polygon calculator constantly, this table was created to show the angles for some of the more commonly encountered regular polygons.

There are just 22 regular polygons that have angles which are integers.

Note: the triangle is sometimes (though rarely) referred to as a trigon and
the square is sometimes referred to as a tetragon.

Polygon       NAME   Polygon     SIDES   Each   Interior    ANGLE   Central     ANGLE   Equals   Exterior     Angle =     Interior       ANGLE     Total       Triangle (Trigon)         3     60   120        180     Square (Tetragon)         4     90     90        360     Pentagon         5   108     72        540     Hexagon         6   120     60        720     Octagon         8   135     45     1,080     Nonagon         9   140     40     1,260     Decagon       10   144     36     1,440     Dodecagon       12   150     30     1,800     Pentadecagon       15   156     24     2,340     Octadecagon       18   160     20     2,880     Icosagon       20   162     18     3,240     Icositetragon       24   165     15     3,960     Triacontagon       30   168     12     5,040     Triacontahexagon       36   170     10     6,120     Tetracontagon       40   171       9     6,840     Tetracontapentagon         45   172       8     7,740     Hexacontagon       60   174       6   10,440     Heptacontadigon       72   175       5   12,600     Enneacontagon       90   176       4   15,840     *****     120   177       3   21,240     *****     180   178       2   32,040     *****     360   179       1   64,440