Practice: A 15 foot ladder is resting against the wall. The bottom is initially 10 feet away from the wall and is being pushed towards the wall at a rate of 1/4 ft/sec. H ow fast is the top of the ladder moving up the wall 12 seconds after we start pushing?

Practice: Each side of a square is increasing at a rate of 4 m?s. At what rate is the area of the square increasing when the are of the square is 16 m^2.