How do you find the center and radius for (x - 9)^2 + (y + 11)^2 = 16(x9)2+(y+11)2=16?

1 Answer
May 28, 2018

"centre "=(9,-11)," radius "=4centre =(9,11), radius =4

Explanation:

"the standard form of the equation of a circle is"the standard form of the equation of a circle is

color(red)(bar(ul(|color(white)(2/2)color(black)((x-a)^2+(y-b)^2=r^2)color(white)(2/2)|)))

"where "(a,b)" are the coordinates of the centre and r"
"is the radius"

(x-9)^2+(y+11)^2=16" is in standard form"

"with "(a,b)=(9,-(-11))" and "r=sqrt16

"centre "=(9,11)" and radius "=4