1. water is falling on the surface, wetting a circular area that is expanding at a rate of 4mm^2/s. How fast is the radius of the wetted area expanding when the radius is 134 mm?
2. A piece of land is shaped like a triangle. Two people start at the right angle of the triangle at the same time, and walk at the same speed along different legs of the triangle. If the area formed by the positions of the two people and their standing point (the right triangle) is changing at 2m^2/s , then how fast are the people moving when they are 5 m from the right triangle?
3. A man 6 ft tall walks at a rate of 6 ft/sec away from a lamppost that is 24 ft high. At what rate is the length of his shadow changing when he is 45 ft away from the lamppost?