Now first we must remember the formula: V - E + F = 2
Now let us look at V. V is the number of vertices, shown below:
Now let us look at E. E is the number of edges, shown below:
Now let us look at F. F is the number of faces, shown below:
To finish up we should plug back into the formula: V - E + F = 2 and solve when V = 4, E = 6, and F = 4...we get 4 - 6 + 4 = 2. And this works
Go back to Euler Problem