Answer:
C. 9π
Explanation:
r=x-1
A=πr^2
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- (x-1)^2+(2x-4)^2= (x-1+2)^2
- x^2-2x+1+4x^2- 16x+16= x^2+2x+1
- 4x^2 -20x +16=0
- x^2-5x+4=0
- (x-1)(x-4)=0
- x=1 - not possible as radius can't be zero
- x=4 is the solution
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A= πr^2= π*(4-1)^2= 9π, option C.