Sliding Ladder problem in AP Calculus

Can someone help me solve this problem.

A. A painter is paint a house using a ladder 15ft long. A dog runs by the ladder dragging its leash that catches the bottom of the ladder and drags it directly away from the house at a rate of 22ft/sec. Assuming the ladder continues to be pulled away form the wall at this speed, how fast is the ladder moving down the wall when the top is 5ft from the ground?

B Find how fast the angle between the ladder and the ground is changing when the top of the ladder is 5ft from the ground?

A. If we let denote the distance the base of the ladder is from the house and denote the height of the top of the ladder on the wall, then assuming the ground is level and the wall vertical, we have a right triangle where the length of the ladder is the hypotenuse. So, how are , and the length of the ladder related?