The equation of a circle C is expr(["+", X2T, Y2T]) = R * R.
What are its center (h, k) and its radius r?
(h, k) = (H, K)
r = {}R
The equation of a circle with center (h, k) and radius r is (x - h)^2 + (y - k)^2 = r^2.
We can rewrite the given equation as (x - negParens(H))^2 + (y - negParens(K))^2 = R^2.
Thus, (h, k) = (H, K) and r = R.