I am trying to determine two dihedral angles for this polyhedron: http://georgehart.com/virtual-polyhedra/vrml/zonish-6-icosidodecahedron.wrl 1. The angle between a pentagon and a square? 2. The angle between a square and a triangle? This polyhedron is formed by adding squares between the pentagons and triangles of an icosidodecahedron, and adding golden rhombi where each of the vertices are. This polyhedron can also be viewed at the top of this page if you do not have the plugin to view the 3D model: http://www.georgehart.com/virtual-polyhedra/zonish_polyhedra.html I know that the dihedral angle between a rhombus and a square is 162°, and that in an icosidodecahedron the dihedral angle is 142.62° between the pentagons and triangles before the squares are added. Any help would be appreciated.