A 14 foot ladder is leaning against a wall. If the top slips down the wall at a rate of 2 ft/s, how fast will the foot of the ladder be moving away from the wall when the top is 9 feet above the ground?

Question

anonymous · Answer

Here is an application of related rates in Calculus. So the best approach is to draw the diagram of the situation  and label all sides. Since the ladder and the wall form a right triangle a key equation would be the Pythagorean theorem which you will implicitly derive and solve for the change in the leg of the triangle you're looking for using the rate of change of the other leg. Notice that the hypotenuse (the ladder) is not changing...so that should make this much easier.