I'm confused by this question and do not know where to start. If I use the chain rule and write , where is the length of the floor from the wall to point and where is the time, what would be?A ladder of length metres has one end leaning against a vertical wall. The other end rests on horizontal ground. When is at a height of metres, it slides down the wall at a rate of . How fast is the other end, , sliding along the horizontal ground? Answer:

I only know that when A is at a height of 4 metres, B must be at 3 metres away from the wall because of the pythagora's theorem.

Any help would be appreciated and thank you in advance.