Solve the all parts of given problem:
Problem: Jim-bob desires to travel 61.3 km directly north. However, he gets confused and ends up 35.5 km directly east of his starting point.
Part A: If Jim-bob now heads directly toward his original destination, how far does he need to travel?
Part B: At what angle (North of west) does Jim-bob need to travel to reach his original destination?
Explain how you came up the prefixes and answer please.