# How do you write the equation of a circle with a center at (-3, -4) and a radius of 3?

Mar 21, 2016

${\left(x + 3\right)}^{2} + {\left(y + 4\right)}^{2} = 9$

#### Explanation:

${\left(x - h\right)}^{2} + {\left(y - k\right)}^{2} = {r}^{2}$
${\left(x - - 3\right)}^{2} + {\left(y - - 4\right)}^{2} = {3}^{2}$
${\left(x + 3\right)}^{2} + {\left(y + 4\right)}^{2} = 9$

Mar 21, 2016

${\left(x + 3\right)}^{2} + {\left(y + 4\right)}^{2} = 9$

#### Explanation:

$C \left(a , b\right) \text{the center coordinates of circle}$
${\left(x - a\right)}^{2} + {\left(y - b\right)}^{2} = {r}^{2}$
$\text{using " a=-3" "b=-4" } r = 3$
${\left(x + 3\right)}^{2} + {\left(y + 4\right)}^{2} = {3}^{2}$
${\left(x + 3\right)}^{2} = {3}^{2} - {\left(y + 4\right)}^{2}$
${\left(x + 3\right)}^{2} + {\left(y + 4\right)}^{2} = 9$