You use Pythagorean theorem which is x^2 +y^2=z^2 (^ this means to the power of) so you would get 55^2+33^2=z^2. solving this would get you z=64.1404708433 or 64.1
Alexander has to miles to go because if one mile is a third you can simply maltiply by three, then subtract the mile he already went. you maltiply by three because it was a third of the way there