A plane flies in a direction of N70°E for 80km, then on a bearing of S10°W for 150km. How far and in what direction is the plane from its starting point?
After making my sketch, and letting the distance to the origin be d , I see
d^2 = 150^2 + 80^2 - 2(150)(80)cos60°
...
d = 130
now that you have d, you can use the sine law to find any angle remaining.
e.g. sin60/d = sinθ/150