Description

ICOSIDODECAHEDRON

The icsosidodecahedron may be formed by joining the midpoints of the edges of either the dodecahedron or the icosahedron.

So it is a kind of mean solid of that pair of solids which are duals of one another.

The ratio of the lengths of the edge to the radius is  the ‘mean and extreme’ ratio also known as  the ‘golden’ ratio or section.