Pronunciation: /doʊˈdɛk əˌgɒn/ Explain

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When does the central angle, the exterior angle, and the interior angle change? Why is this?
Manipulative 1 - Regular Dodecagon Created with GeoGebra.

A dodecagon is a polygon that has 12 sides.[1] A regular dodecagon is a 12 sided regular polygon. The variable s in the formula in table 1 is the length of one of the sides of a regular dodecagon.

r=(1/2)(2+square root of 3)sInradius: The radius of the incircle.
R=(1/2)(square root of 2+square root of 3)sCircumradius: The radius of the circumcircle.
r=3(2+square root of 3)s^2Area
Table 1: Regular Dodecagon Formulas.


  1. Stöcker, K.H.. The Elements of Constructive Geometry, Inductively Presented. pg 28. Translated by Noetling, William A.M, C.E.. Silver, Burdett & Company. 1897. Last Accessed 8/6/2018. Buy the book

Cite this article as:

McAdams, David E. Dodecagon. 7/4/2018. All Math Words Encyclopedia. Life is a Story Problem LLC.

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Revision History

7/4/2018: Removed broken links, updated license, implemented new markup, implemented new Geogebra protocol. (McAdams, David E.)
12/31/2009: Added "References". (McAdams, David E.)
12/15/2008: Initial version. (McAdams, David E.)

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