The Dodecahedron


The regular dodecahedron is a Platonic solid bounded by 12 regular pentagons. It has 20 vertices and 30 edges.

A
dodecahedron

The dual of the dodecahedron is the icosahedron. The dodecahedron occurs as cells in the 120-cell and the runcinated 120-cell.

Projections

In order to be able to identify the dodecahedron in various projections of 4D objects, it is useful to know how it appears from various viewpoints. The following are some of the viewpoints that are commonly encountered:

Projection Envelope Description
Non-regular dodecagon

Vertex-first parallel projection.

Non-regular hexagon

Edge-first parallel projection. Four of the dodecahedron's faces project onto 4 of the edges of the hexagonal envelope.

Regular decagon

Face-first parallel projection.

Non-regular octagon

Parallel projection parallel to top and bottom faces. The top and bottom faces project to the top and bottom edges of the projection envelope.

Coordinates

The canonical Cartesian coordinates for the dodecahedron are:

where φ=(1+√5)/2 is the Golden Ratio.

These coordinates give a dodecahedron with edge length 2/φ, or approximately 1.236.


Last updated 08 Aug 2012.

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