The ancient Greek mathematician Euclid proved in his Elements of Geometry that there are only five Platonic solids – the regular tetrahedron (four sides that are equilateral triangles), the cube (six ...

A 3D shape with regular polygonal faces, meeting at equal angles, is a platonic solid. There are five platonic solids, the tetrahedron, cube, octahedron, dodecahedron and icosahedron. A prism is a ...