Find the Center and Radius:
A circle w/ (-5,4) & (-6,-3) as ends of a diameter
If the ends of the diameter are (-5,4) and (-6,-3), then the center of the circle is the midpoint of the said diameter, which is
((-5+(-6))/2,(4+(-3))/2) = (-5.5,0.5) -------------answer.
The radius then is
r = sqrt[(-5.5 -(-5))^2 +(0.5 -4)^2)
r = sqrt[(-0.5)^2 +(-3.5)^2]
r = sqrt[0.25 +12.25]
r = sqrt(12.5) = 3.535534 ---------------answer.