math
posted by Thano .
Now imagine a circle with a 3mile radius to be a hypothetical metropolitan area with relatively little undeveloped land inside. If the radius of this hypothetical metropolitan area is extended to 10 miles, how much land is added to the original developed area? (Note: Use 3.1416 as the value of ð in your formula for the area of your circle. There are 640 acres in a square mile.)

math 
Reiny
The original area with a 3 mile radius was 9pi square miles
The new area with a 10 mile radius is 100pi square miles
So the new area added is 91pi square miles or
91*3.1416*640
= 182,967 acres
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