# A circle has the equation (x + 1)^2 + (y - 3)^2 = 16. What are the coordinates of its center and length of radii?

Jan 22, 2016

Have a look:

#### Explanation:

You can think at the general equation of a circle:
${\left(x - h\right)}^{2} + {\left(y - k\right)}^{2} = {r}^{2}$
where:
$h , k$ are the coordinates of the center;
$r$ is the radius.

$h = - 1$
$k = 3$
$r = \sqrt{16} = 4$