# How do you find the center and radius of the circle  (x+9)^2 + (y-5)^2 = 64?

Jun 11, 2016

centre (-9 ,5) , radius = 8

#### Explanation:

The standard form of the equation of a circle is.

$\textcolor{red}{| \overline{\underline{\textcolor{w h i t e}{\frac{a}{a}} \textcolor{b l a c k}{{\left(x - a\right)}^{2} + {\left(y - b\right)}^{2} = {r}^{2}} \textcolor{w h i t e}{\frac{a}{a}} |}}}$
where (a ,b) are the coordinates of the centre and r, the radius.

From the given equation we should see that

a = -9 , b = 5 and r = 8

hence centre = (-9 ,5) and radius = 8