Pronunciation: /aɪˌkoʊ səˈhid rən/ ?

Regular icosahedron
Figure 1: Regular icosahedron. Click here for to see a rotating icosahedron.

An icosahedron is any 20-sided polyhedron.[1] A regular icosahedron has congruent 20 sides, 12 vertices and 30 edges. Each side is an equilateral triangle. The Euler-Descarte formula for an icosahedron is 12 + 20 - 30 = 2. The word 'icosahedron' comes from 'icos', which is derived from the Greek word for twenty and 'hedron', which comes from the Indo-European word for seat.

A geometric net is a 2-dimensional figure that can be folded into a 3-dimensional shape. Click for a geometric net you can fold into an icosahedron.

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Cite this article as:

Icosahedron. 2010-02-11. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/i/icosahedron.html.


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Revision History

2010-02-11: Added "References" (McAdams, David.)
2008-08-09: Added More Information, information about vertices and edges, and derivation of the word (McAdams, David.)
2008-06-09: Initial version (McAdams, David.)

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