SOLUTION: Find the area of the region between two concentric circles with radii 9 and 6.

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Question 77707: Find the area of the region between two concentric circles with radii 9 and 6.
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
Find the area of the region between two concentric circles with radii 9 and 6.
:
If "concentric" means that the smaller circle is inside the larger circle, then we subtract the area of the smaller circle from the area of the larger circle.
:
The formula for the area of a circle is highlight%28A=pi%2Ar%5E2%29 A=area, r=radius, pi is approximately 3.141592654
The area of the larger circle with r=9 is:
A=pi%2A%289%29%5E2
A=81%2Api
The area of the smaller circle with r=6 is:
A=pi%2A%286%29%5E2
A=36%2Api
The difference is:
81%2Api-36%2Api=45%2Api
You can approximate this to whatever your teacher wants. A lot will let you use pi=3.14
45%2A3.14=141.3
Happy Calculating!!!