Please help with an explanation on related rates. I'm super lost from start to end.

6103 II" LTE C} Take Quiz Exit prof. G D Question 1 1 pts Solve the problem below and submit the work : One end of 5 ft ladder is on the ground and the other end rests on a vertical wall. The bottom end of the ladder is drawn away from the wall at 7ft/s. How fast is the top of the ladder sliding down the wall when the foot of the ladder is 3 feet from the wall? Upload Choose a File Quiz saved at 6:02pm Submit Quiz Time Elapsed: Hide