Platonic Solids

The five perfect shapes

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• There are exactly five Platonic solids: 4, 6, 8, 12 and 20 faces.
• The angles at a corner must add up to less than 360°, which limits the possibilities.
• Count edges by counting face-edges and halving.

Steps

1. Perfect dice
2. The five solids
3. Why only five?
4. Dual solids
5. Missing angles
6. Counting edges