Icosahedron

Pronunciation: /aɪˌkoʊ səˈhid rən/ ?

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

An icosahedron is a 20-sided polyhedron.[1] A regular icosahedron has congruent 20 sides, each one of which is an equilateral triangle. A regular icosahedron has 30 edges and 12 vertices. 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.

More Information

• McAdams, David. Geometric Net of a Regular Icosahedron. lifeisastoryproblem.org. Life is a Story Problem.org. 2010-02-11. http://www.lifeisastoryproblem.org/explore/net_icosahedron.pdf.

Cite this article as:

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

Translations

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Image Credits

• All images and manipulatives are by David McAdams unless otherwise stated. All images by David McAdams are Copyright © Life is a Story Problem.org and are licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.
• Figure 1: Regular icosahedron: André Kjell. Licensed under the terms of the GNU Free Documentation License, Version 1.2 or any later version. http://en.wikipedia.org/wiki/File:Icosahedron.gif

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.)