Platonic Solids

Definition

A platonic solid is a regular convex polyhedron.

For a regular polyhedron:

  • All faces are congruent regular polygons.

  • Same number of faces adjacent to each vertex.

  • Dihedral angle (Angle between 2 planes) are equal between each face.

Explore!

Use the applet below to explore the properties of the 5 Platonic Solids.

Can you prove that there are only 5 possible platonic solids?

Hint! The angle defect for polygons around each vertex must be positive in order for the polyhedral net to fold into a polyhedron.

Next: You can unfold the nets of the 5 platonic solids here.