Question 42689
An equation in the form {{{ (x-h)^2 +(y-k)^2 = r^2}}} is the equation of a circle, whose radius is r, and whose center is at (h,k).  In other words, you have to ZERO out the quantities that are squared, and those are the values that gives the center of the circle.


In your case, the center is at x=0 and y = -1, and the radius is r^2= 9, so r=3.


R^2 at SCC