see question below

Question

The radius of a circular oil spill is increasing at a rate of 10 feet per hour. How quickly is the surface area changing when the radius is 200 feet?

Answer 1

serkel area=pi*radius*radius

rad=200ft...area=40000 pi

radius gro at 10 ft/our

1 our later, rad=210 ft...delta rad=10/200=1/20=5%

210^2=44,100

delta=4,100

4100/40000=0.1025 or 10.25%

area % =2* radius %