Find the center and radius of the circle with equation (x - 3)² + (y + 6)² = 81. A) center = (3, -6), r = 81 B) center = (3, -6), r = 9 C) center = (-3, 6), r = 9 D) center = (-3, 6), r = 81

Question

Quizplus · Accepted Answer

The equation of a circle in the form $(x - h)^2 + (y - k)^2 = r^2$ has a center at $(h, k)$ and a radius $r$. For the given equation $(x - 3)^2 + (y + 6)^2 = 81$, the center is $(3, -6)$ and the radius is $\sqrt{81} = 9$.

Find the Center and Radius of the Circle with Equation