ec2-3-239-59-31.compute-1.amazonaws.com | ToothyWiki | RecentChanges | Login | Webcomic A polyhedron (plural: polyhedra) is a many-faced 3-dimensional shape. A regular polyhedron has identical faces all with sides of the same length, and vertices of the same angle.
That definition leaves something to be desired - I think it would make any double-pyramid regular.
It would indeed. I think we want...
I don't think it would. Mind you, I'm currently trying to work out why two tetrahedra, base to base, aren't regular. My poor brain.
Because there are 4 triangles around each of the glued vertices, and only 3 around the two unglued vertices. I'm not sure your example actually fits "vertices of the same angle".
A regular polyhedron has identical regular-polygonal faces, meeting in identical configurations around each point.