The regular convex polyhedra are the five Platonic solids, which have been known since classical Greece. The ancient Greek mathematician Euclid proved in his Elements of Geometry that there are only ...

A triangle has three sides ... prism.The cross-section is a pentagon.The 3D shape is a pentagonal prism. For all polyhedra the number of edges is two less than the sum of the number of vertices ...

A polyhedron with eight vertices that had more volume than any other eight-vertex shape previously known.” He adds: “It is made completely from triangles.” Mr. Parker is a self-described ...