Question 1179516
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
(0, 0); 3
{{{(x-0)^2 + (y-0)^2 = 9}}} 
{{{x^2 + y^2 = 9}}} is the equation of the circle with the given center and radius.