The Base of a 80-Ft Ladder Leaning Against a Wall

Short Answer

The base of a 80-ft ladder leaning against a wall begins to slide away from the wall. At the instant of time when the base is 64 ft from the wall, the base is moving at the rate of 9 ft/sec. How fast is the top of the ladder sliding down the wall at that instant of time? Round the answer to the nearest tenth, if necessary. __________ ft/sec