Qa.) State the contrapositive of the following implication. If G is a connected planar graph then G has at least one vertex of degree <= 5.
Qb.) Prove the contrapositive stated in part (a). Hint: use the fact that if G is a connected Planar graph , then e <= 3v-6.
Qc.) Use part (a) to show that every planar graph can be colored with 6 (or less) colors. Hint: Use a proof by Induction on the number of vertices G.