Octagon

Pronunciation: /ˈɒk təˌgɒn/ ?

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Manipulative 1: Octagon Created with GeoGebra.

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Manipulative 2: Regular octagon Created with GeoGebra.

A octagon is any eight sided polygon.[1] A regular octagon is an eight-sided polygon with sides of equal length.

Click on the blue points in manipulatives 1 and 2 and drag them to change the figure. As long as the sides do not intersect, the figure in manipulative 1 is an octagon. The figure in manipulative 2 is a regular octagon. To see the various parts of a regular octagon, click on the check boxes.

Octagon Facts
NameValue
Central Anglebeta=45 degrees or p/4 radians.
Vertex Anglealpha=135 degrees or (3pi)/4 radians.
Exterior Anglegamma=225 degrees or (5pi)/4 radians
Inradiusr=(1/2)*(1+square root(2))
Circumradius(1/2)*square root(4+2*square root(2)
Arear=2*(1+square root(2))s^2
Table 1

Geometric Nets Using Octagons
Octagonal Prism
Octagonal Antiprism
Table 2

Examples of Octagons

Stop sign

References

  1. octagon. http://wordnet.princeton.edu/. WordNet. Princeton University. (Accessed: 2011-01-08). http://wordnetweb.princeton.edu/perl/webwn?s=octagon&sub=Search+WordNet&o2=&o0=1&o7=&o5=&o1=1&o6=&o4=&o3=&h=.

Cite this article as:


Octagon. 2009-12-21. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/o/octagon.html.

Translations

Image Credits

Revision History


2009-12-21: Added "References" (McAdams, David.)
2008-12-30: Changed equations to images (McAdams, David.)
2008-07-01: Initial version (McAdams, David.)

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