A dodecagon is a polygon with 12 sides and 12 vertices.
A regular dodecagon is a polygon with 12 equal sides and angles.
Angles of the Dodecagon
The sum of interior angles of a dodecagon = (12 − 2) · 180° = 1,800°
The value of an interior angle of a regular dodecagon is: 1,800º : 12 = 150º
The central angle of a regular dodecagon measures: 360º : 12 = 30º
Diagonals of the Dodecagon
The number of diagonals in a regular dodecagon = 12 · (12 − 3) : 2 = 54
Perimeter of a Regular Dodecagon
Perimeter = 12 · l
Area of a Regular Dodecagon