Question 426645
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Hi
Finding the center and the radius of the circle by completing the square
Standard Form of an Equation of a Circle is {{{(x-h)^2 + (y-k)^2 = r^2}}}
where Pt(h,k) is the center and r is the radius

x^2+y^2-18x+4y+4=0
(x-9)^2-81 + (y+2)^2-4 + 4 = 0
(x-9)^2 + (y+2)^2 = 81
  C(9,-2) r  = 9