SOLUTION: Circle O (not shown) has an area of 81π square units. Circle P had a radius that is 2 units shorter than the radius of circle O . What is the diameter of circle P?
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Question 1141982: Circle O (not shown) has an area of 81π square units. Circle P had a radius that is 2 units shorter than the radius of circle O . What is the diameter of circle P? Found 2 solutions by Boreal, ikleyn:Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! area is pi*r^2
81*pi=r^2
r^2=81
r=9 units
circle of radius of 7 units would have an area of pi*7^2=49pi square units
The area of the circle O is
= ;
hence, = 81 and r= = 9 units.
Then the radius of the circle P is (9-2) = 7 units and its diameter is 2*7 = 14 units. ANSWER
