I hope I get a response today...haha. Anyways, if anyone could help me figure this problem out. It'll be greattt...

A math teacher is on top of a 20 foot ladder leaning against a wall when the bottom starts to slip away from the wall. The bottom of the ladder is moving away from the wall at 3 feet per second. How fast is the math teacher approaching the ground when they are 12 feet from the ground?