# Icosahedron

*Icosahedron* is one of only five Platonic solids. This is a regular polyhedron with 12 vertices, 30 edges, and 20 faces. All faces are regular triangles and at every vertex meet five faces and five edges.

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Drag the mouse to rotate the icosahedron. Use the right button to remove and put back individual faces.

(**Acknowledgement**: I have learned most of Java details from the implementation by Meiko Rachimow.)

The word *icosahedron* originates with the Greek *eikosi* (20). The other Platonic solids are tetrahedron, octahedron, dodecahedron, cube. With 20 faces, 30 edges, and 12 vertices a dodecahedron confirms to the Euler's theorem:

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Copyright © 1996-2017 Alexander Bogomolny

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