An extensible ladder rests vertically against the side of a 10 foot wall. You start dragging the bottom of the ladder along the floor away from the wall at a rate of 0.5 ft/sec. At the moment when the wall makes a 60 degree angle with the ladder, how fast is the distance between bottom and top of the ladder changing?
I'm unsure how to make my equation. I think I'm supposed to start with a trigonometry function, but I'm not sure how to start.