"PLATONIC SOLIDS" geometric elements.
Platonic solids are five convex regular polyhedra in which all faces are congruent (equal) regular polygons and the same number of faces meet at each vertex. These include the tetrahedron, cube (hexahedron), octahedron, dodecahedron, and icosahedron.
List and parameters
Tetrahedron: 4 faces, 6 edges, 4 vertices.
Cube (hexahedron): 6 faces, 12 edges, 8 vertices.
Octahedron: 8 faces, 12 edges, 6 vertices.
Dodecahedron: 12 faces, 30 edges, 20 vertices.
Icosahedron: 20 faces, 30 edges, 12 vertices.
Why are there only five?
The requirement for identical regular faces and the same number of them at each vertex leaves only a few possible combinations: with triangles, we get a tetrahedron, octahedron, and icosahedron; with squares, only a cube; with pentagons, only a dodecahedron. When attempting to use more “flat” polygons or to assemble too many faces at one vertex, the geometric structure either loses its convexity or becomes impossible.
Connection with Plato's philosophy
In Timaeus, Plato correlated the four elements of nature with solids: fire — tetrahedron, air — octahedron, water — icosahedron, earth — cube. He attributed the fifth body, the dodecahedron, to the structure of the cosmos as a whole, pointing to its special role in the universe.
Key features
These polyhedra have the maximum possible symmetry among convex bodies, and their vertices and edges are equivalent in location. In mathematics, they are also called regular polyhedra, emphasizing the equality of faces, edges, and dihedral angles.