3π
6π
9π
12π
Correct answer is C
Equation of a circle: (x−a)2+(y−b)2=r2
Given that x2+y2−4x+8y+11=0
Expanding the equation of a circle, we have: x2−2ax+a2+y2−2by+b2=r2
Comparing this expansion with the given equation, we have
2a=4⟹a=2
−2b=8⟹b=−4
r2−a2−b2=−11⟹r2=−11+22+42=9
r=3
Area=πr2=π×32
= 9π
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