# How do you write the equation in standard form of the circle center at P(2, -5) and a diameter of 8 units?

Jan 25, 2016

${\left(x - 2\right)}^{2} + {\left(y + 5\right)}^{2} = 64$

#### 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 ) are coordinates of centre and r , the radius.

In this question (a , b ) = (2 , - 5 ) and r = 4 ( since d = 8 )

equation is : ${\left(x - 2\right)}^{2} + {\left(y + 5\right)}^{2} = 16$