ANSWER
65 km
EXPLANATION
Let's do a diagram of the path Harold took,
As we can see, the path forms a right triangle where the shortest distance from the starting point, d, is the hypotenuse. Using the Pythagorean theorem we can find d,
[tex]d=\sqrt[]{33^2+56^2}=\sqrt[]{1089+3136}=\sqrt[]{4225}=65[/tex]Hence, the shortest distance from his starting point is 65 km.