A girl drives 3.9 km north, then 13.1 km to the northwest, and finally 4.58 km south-southwest. What is her displacement in terms of the unit vectors with pointing east and pointing north?
3.9 N is (0,3.9)
13.1 NW is (-9.48,9.48)
4.58 SSW is (-1.75,-4.23)
Add 'em up to get (-11.23,9.15) or 14.5 @ N51°W