posted by Nicole .
Show that Euler's formula holds for a right pentagonal prism.
His formula for polyhedra is
Vertices - Edges + Faces = 2
Sketch two congruent pentagons, one above the other.
Join corresponding vertices, perhaps with dotted lines for the lines that are hidden.
You should have a nice drawing of your solid.
Number of vertices = 10
number of edges = 15
number of faces = 7
is 10 - 15 + 7 = 2 ??