Points of coordinates:

are the 20 vertices of a regular dodecahedron of edge 2.

Where Phi is the golden ratio we've seen in the golden rectangle.

We can calculate the distance between pairs of adjacents vertices to convince ourselves.

This is an interesting step in understanding properties of this polyhedron, for example, the volume of a regular dodecahedron.

One eighth of a dodecahedron of side 2 has the same volume as a dodecahedron of side 1.

LINKS

	Volume of a regular dodecahedron (Flash version) One eighth of a regular dodecahedon of edge 2 has the same volume as a dodecahedron of edge 1.
	The golden rectangle A golden rectangle is made of an square and another golden rectangle.
	The icosahedron and its volume The twelve vertices of an icosahedron lie in three golden rectangles. Then we can calculate the volume of an icosahedron
	The volume of the tetrahedron The volume of a tetrahedron is one third of the prism that contains it.
	Volume of an octahedron The volume of an octahedron is four times the volume of a tetrahedron. It is easy to calculate and then we can get the volume of a tetrahedron.
	The volume of a truncated octahedron The truncated octahedron is an Archimedean solid. It has 8 regular hexagonal faces and 6 square faces. Its volume can be calculated knowing the volume of an octahedron.