Octagon

Pronunciation: /ˈɒk təˌgɒn/ Explain

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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

Cite this article as:

McAdams, David E. Octagon. 5/5/2011. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/o/octagon.html.

Image Credits

Revision History

12/21/2009: Added "References". (McAdams, David E.)
12/30/2008: Changed equations to images. (McAdams, David E.)
7/1/2008: Initial version. (McAdams, David E.)

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