Question 1014485
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Find radius (distance from center to point on circle)
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{{{P[1]=center}}}=(2,-1); {{{P[2]}}}=(-1,2)
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{{{d=sqrt((x[2]-x[1])^2+(y[2]-y[1])^2)}}}
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{{{r=sqrt((-1-2)^2+(2-(-1))^2)}}}
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{{{r=sqrt((-3)^2+(3)^2)}}}
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{{{r=sqrt(9+9)}}}
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{{{r=3sqrt(2)}}}
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Equation for circle:
center=(h,k)=(2,-1)
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{{{(x-h)^2+(y-k)=r^2}}}
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{{{(x-2)^2+(y+1)^2=(3sqrt(2))^2}}}
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{{{(x-2)^2+(y+1)^2=18}}}
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CHECK:
Substitute point (-1,2) for x and y.
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{{{(x-2)^2+(y+1)^2=18}}}
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{{{(-1-2)^2+(2+1)^2=18}}}
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{{{(-3)^2+(3)^2=18}}}
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{{{9+9=18}}}
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{{{18=18}}}