# The center of a circle is at (4, -1) and it has a radius of 6. What is the equation of the circle?

Mar 6, 2016

${\left(x - 4\right)}^{2} + {\left(y + 1\right)}^{2} = 36$

#### Explanation:

The standard form of the equation of a circle is :

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

where (a , b ) is the coords of the centre and r , the radius.

here (a , b ) = (4 , -1 ) and r = 6

substitute these values into the standard equation

$\Rightarrow {\left(x - 4\right)}^{2} + {\left(y + 1\right)}^{2} = 36 \text{ is the equation }$