1. The problem statement, all variables and given/known data By considering the vertices of the pentagon, show that D5 is isomorphic to a subgroup of S5. Write all permutations corresponding to the elements of D5 under this isomorphism. 3. The attempt at a solution To show isomorphic, need to find a function f: D5->S5, where f(a,b) = f(a)f(b), f is one to one and onto. I'm having a hard time determining the elements of of D5. D4 was trivial, but this one doesn't make sense to me.