Calculus
posted by Z32 .
A 25 foot ladder is leaning on a 9 foot fence. The base of the ladder is being pulled away from the fence at the rate of 10 feet/minute. How fast is the top of the ladder approaching the ground when the base is 9 from the fence? [Note: The ladder is protruding over the top of the fence.]

Before I start typing a rather messy solution, do you know if the correct answer is
10.1788 ft/min ? 
Not correct.

A 25 foot ladder is leaning on a 9 foot fence. The base of the ladder is being pulled away from the fence at the rate of 10 feet/minute. How fast is the top of the ladder approaching the ground when the base is 9 from the fence? [Note: The ladder is protruding over the top of the fence.]