# Given (x+10)^2+(y-3)^2=121 what is the radius of this circle?

Nov 30, 2015

The radius of the circle is $11$

#### Explanation:

In the equation of a circle:

${\left(x - a\right)}^{2} + {\left(y - b\right)}^{2} = {r}^{2}$

you can write that:

• the radius of the circle is $r$
• the circle's center has coordinates: $\left(a , b\right)$

So in your equation the radius is $\sqrt{121} = 11$ and the centre is (-10;3)