what is the center and radius of the circle represented by the following equation: (x+3)^2 + (y-6)^2=81?
When the equation of a circle is in this format:
(x - h)2 + (y - k)2 = r2 ,
The center of the circle is (h, k) and the radius is r.
So...if the equation of a circle is:
(x + 3)2 + (y - 6)2 = 81
h = -3
k = 6
r2 = 81
r = \(\sqrt{81}\)
r = 9
The center of the circle is (-3, 6) and the radius is 9.