The Icosahedron

A polyhedron bounded by twenty equilateral triangles; five meeting at each vertex.

The icosahdedron is one of the five platonic solids.

Vertex
Symbol
Wythoff
Symbol
No. of
Vertices
No. of
Edges
No. of
Faces
Symmetry
Group
Dual Polyhedron
35 5 | 2 3 12 30 20 A5×C2 Dodecahedron

Edge ratios:

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