Identify the center and radius of the circle. $$( x + 8 ) ^ { 2 } + ( y - 9 ) ^ { 2 } = 121$$
A) Center $= ( - 8,9 ) ; r = 11$
B) Center $= ( 8,9 ) ; r = 11$
C) Center $= ( 8 , - 9 ) ; r = 11$
D) Center $= ( - 8,9 ) ; r = 121$

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 $r$. Here, the equation $(x + 8)^2 + (y - 9)^2 = 121$ matches this form with $h = -8$, $k = 9$, and $r^2 = 121$, which means $r = 11$.

Identify the Center and Radius of the Circle (x+8)2+(y−9)2=121( x + 8 ) ^ { 2 } + ( y - 9 ) ^ { 2 } = 121(x+8)2+(y−9)2=121

Identify the Center and Radius of the Circle $( x + 8 ) ^ { 2 } + ( y - 9 ) ^ { 2 } = 121$