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

##### 1 Answer

May 28, 2018

#### Explanation:

#"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#