A tridecagon or triskaidecagon is a polygon with 13 sides and 13 vertices.
A regular tridecagon is a polygon with 13 equal sides and angles.
Angles of the Tridecagon
The sum of interior angles of a tridecagon = (13 − 2) · 180° = 1,980°
The value of an interior angle of a regular tridecagon is: 1,980º : 13 = 152.31º
The central angle of a regular tridecagon measures: 360º : 13 = 27.69º
Diagonals of the Tridecagon
The number of diagonals in a regular tridecagon = 13 · (13 − 3) : 2 = 65
Perimeter of a Regular Tridecagon
Perimeter = 13 · l
Area of a Regular Tridecagon