First correct answer gets best answer with explanation

The area of a circular oil spill is increasing at a rate of 5 ft sq / min. At what rate is the radius of spill increasing when the radius is 10 ft.?

The area of a circular oil spill is increasing at a rate of 5 ft sq / min. At what rate is the radius of spill increasing when the radius is 10 ft.?

The area of the latter circle is 20pi ft, which has four times the area of the first circle (20/5=4). For example if the area of the first circle is 10, than we can conclude that d=rt, or 10=5t and t=2 minute. Now since we know the first and second circle has a ratio of four, then the second we can incorporate 40=5t, t=8 minute. Thus, the rate of the spill for the second circle is 1/4 the rate of the first fircle; r=1/4 minute. So if the rate for 5 ft sq / min for circle one, than the rate for circle two is 5/4 ft sq / min.

~David

5 ft sq / min because the rate is always going to be a constant until the rig runs out of oil.