Unit C Problem Set Directions: Complete the problems on this sheet or on your own paper. Show all work and include appropriate units where applicable. Box all final answers. 1. When oil was spilled out in the middle of a lake, it spread out on the surface of the water in a circular pattern. The radius of the circular pattern increased at a rate of 5 feet per minute. ( r(t) = 5t ft/min ) A. [3 pts] How fast was the area of the circular pattern increasing per minute? Construct the composite function to show how the area was increasing each minute. ( A(r) = mr2 ft2 / min ). B. [2 pts] Find the radius of the circular pattern of oil 90 seconds after the oil starts to spread. C. [2 pts] Find the area of the circular pattern of oil 3 minutes after the oil starts to spread