5 Platonic Solids - Numberphile
Why are there just five platonic solids (and what are platonic solids!?) More links & stuff in full description below ↓↓↓ The solids are the tetrahedron, hexahedron (cube), octahedron,...
==========
KATIE STECKLES: I would like to talk to you about the number 5. And the thing that I like most about the number 5 is that there are only five platonic solids. JAMES GRIME: This is a regular polygon. It's a regular triangle. And it has the same number of triangles meeting at each corner. KATIE STECKLES: The definition of a platonic solid is a shape where you've got sort of different sides to the shape, but all of the sides are the same shape. That shape is a regular kind of polygon-- so like a square where all the sides are the same length and the angles are the same and every corner looks the same. So those are the conditions. JAMES GRIME: And this is, in fact, called a tetrahedron. It's like a pyramid. But it's got a triangular base...
==========
KATIE STECKLES: I would like to talk to you about the number 5. And the thing that I like most about the number 5 is that there are only five platonic solids. JAMES GRIME: This is a regular polygon. It's a regular triangle. And it has the same number of triangles meeting at each corner. KATIE STECKLES: The definition of a platonic solid is a shape where you've got sort of different sides to the shape, but all of the sides are the same shape. That shape is a regular kind of polygon-- so like a square where all the sides are the same length and the angles are the same and every corner looks the same. So those are the conditions. JAMES GRIME: And this is, in fact, called a tetrahedron. It's like a pyramid. But it's got a triangular base...
