Suppose two angles in a coordinate plan, one measuring 80 and the other measuring 160 ,were both rotated 180 about the origin and then translated 40 units down

Atourist boat is used for sightseeing in a nearby river. the boat travels 2.4 miles downstream and in the same amount of time, it travels 1.8 miles upstream. if the boat travels at an average speed of 21 miles per hour in the still water, find the current of the river.