Dodecagon - Definition and Overview

A regular dodecagon

A dodecagon is a polygon with exactly twelve sides. All sides on a dodecagon are convex, i.e. there are no concavities. When spelled uppercase, the letters E and H (and I in a serif font) are all dodecagons.

A regular dodecagon is a dodecagon with all sides having equal length and all angles having the same number of degrees, and this number is 150. The area of a regular decagon is given by

<math>A = 3 a^2 \cot \frac{\pi}{12} \simeq 11.1962 a^2.<math>

See also

• decagon
• enneagon
• geometry
• heptagon
• hendecagon
• hexagon
• octagon
• pentagon
• quadrilateral
• triangle

External links

• Dodecagon and Kurschak's Tile and Theorem (http://agutie.homestead.com/files/kurschak1.html) by Antonio Gutierrez from "Geometry Step by Step from the Land of the Incas"
• Dodecagon (http://mathworld.wolfram.com/Dodecagon.html) at MathWorld