The faces of a planar p-regular graph are all triangles (that is each face has degree three). Determine, with proof, the values of p for which this is possible. (Remember a p-regular graph has all vertices of degree p).
Values of p for which the faces of a planar p-regular graph are all triangles are found. The solution is detailed and well presented. The solution received a rating of "5" from the student who posted the question.