Question

What is the radius of the circle shown below?
x^2+y^2-2x+6y+9=0

Answer 1

1

Explanation:

The graph below shows the radius to be 1.

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If we rewrite the equation to standard form, we have ...

(x^2 -2x +1) +(y^2 +6y +9) = -9 +1 +9

(x -1)^2 +(y +3)^2 = 1

The square of the radius is 1, so the radius is 1.