Final answer:
The displacement from point A to point C is 4.5 km in the northeast direction.
Step-by-step explanation:
The displacement from point A to point C can be calculated by considering the displacement vector from point A to point B and the fraction of the distance from A to B that is covered by point C. According to the given information, the displacement vector from point A to point B is represented as ĎAB with a magnitude of DAB = 6 km and a northeast direction. The displacement from point A to point C, which is represented as ĎAC, can be determined using the equation ĎAC = 0.75ĎAB. This means that the magnitude of ĎAC is 0.75 times the magnitude of ĎAB, which is 4.5 km in this case. Furthermore, ĎAC is parallel to ĎAB, meaning they have the same direction. Therefore, the displacement from point A to point C is 4.5 km in the northeast direction.