Given $G$ a graph with degrees:$6,6,4,4,4,k,k$ on $7$ vertices and $10$ regions
(and by Euler $n-f+r=2$ I found that $k$=3)
prove $G$ is contains a Hamiltonian cycle
I did find a visual cycle on the actual graph, where in the solutions (by a student) he proved that vertex 3 doesn't have to be a neighbor with the other vertex degree 3 and thus by the theorem the graph is hamiltonian
What will be a better explanation in a discrete math course
Here it is... a Hamiltonian cycle in your graph: