Polygons and PolyhedraPolyhedra

Up to now we have just looked at what we can do with polygons in a flat, two-dimensional world. A polyhedron is a three-dimensional object that is made up of polygons. Here are some examples:

Polyhedra cannot contain curved surfaces – spheres and cylinders, for example, are not polyhedra.

The polygons that make up a polyhedron are called its faces. The lines where two faces are connected are called edges, and the corners where the edges meet are called vertices.