Pronunciation: /doʊˈdɛk əˌgɒn/ ?

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Manipulative 1: Dodecagon. Created with GeoGebra.

A dodecagon is a polygon that has 12 sides.[1] A regular dodecagon is a 12 sided regular polygon. Click on the blue points in manipulative 1 and drag them to change the figure. Click on the check boxes in manipulative 1 to see properties of a regular dodecagon. 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. dodecagon. WordNet. Princeton University. (Accessed: 2011-01-08).
  2. Stöcker, K.H.. The Elements of Constructive Geometry, Inductively Presented, pg 28. Translated by Noetling, William A.M, C.E.. Silver, Burdett & Company, 1897. (Accessed: 2009-12-31).

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Dodecagon. 2009-12-31. All Math Words Encyclopedia. Life is a Story Problem LLC.


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Revision History

2009-12-31: Added "References" (McAdams, David.)
2008-12-15: Initial version (McAdams, David.)

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