# The Dodecahedron

A polyhedron bounded by twelve regular pentagonal faces; three meeting at each vertex.

The dodecahedron is one of the five platonic solids.

 VertexSymbol WythoffSymbol No. ofVertices No. ofEdges No. ofFaces SymmetryGroup Dual Polyhedron 53 3 | 2 5 12 30 20 A5×C2 Icosahedron

Edge ratios:

• e/r = sqrt(50-22sqrt(5))
• e/rho = 3 - sqrt(5)
• e/R = (sqrt(5)-1)/sqrt(3)

where e is the edge length, r is the in-radius, rho is the inter-radius, and R is the circum-radius.