In this lesson we explore why there are only five platonic solids. This lesson was adapted from a session at the Houston Circle on the Road.
In this lesson we quickly review polygons, convex polygons and regular convex polygons. We discuss the angle measure of regular polygons and then define what a platonic solid is. After this, the teachers are given a set of Polydrons and asked how many platonic solids there are.
The teachers are given time to build what they think are all of the platonic solids and then there is a whole group discussion of whether or not they have found all of them and how they know that there are no more.