3 . C —The velocities of the boat and the current must be added to produce a resultant that points
directly north as shown. The angle θ is found by using 4 . D —The velocities of the boat and current are added as shown in the figure, which forms a right
triangle. The resultant velocity can be found using the Pythagorean theorem or by realizing that this is
a 3-4-5 triangle.