The Platonic solids are five polyhedrons (solids with flat faces).

They have the following special properties:

• Every face of a Platonic solid is the same regular polygon (same size, same shape)
• They have no dents in them (they are convex)

For example, the cube is a Platonic solid. Every face of the cube is a square of the same shape.

A tetrahedron in which every face is an equilateral triangle is a Platonic solid.

The Platonic solids are named after the Greek philosopher and mathematician, Plato, who thought that they made up the classical elements of earth, water, air and fire.