Solve the all parts of given question:
Question: An airplane flies 200 km due west from city A to city B and then 280 km in the direction of 24.5° north of west from city B to city C.
Part A: In straight-line distance, how far is city C from city A?
__________ km
Part B: Relative to city A, in what direction is city C?
__________ ° north of west
Please give a full detailed explanation of solution for above question.