posted by ggift .
If a polyhedron has 13 vertices and 21 faces, how many edges does it have? I can't figure this one out.
Use Euler's formula which says that
For example, a cube has 8 vertices, 6 faces and 12 edges, so
For a given polyhedron, there are 24 vertices and 32 faces. How many edges does the polyhedron have? [Hint: V + F = E + 2.]