# How do you find the radius and center of a circle with the equation ( x - 1) ^2 + (y - 3) ^2 =16?

Mar 13, 2016

radius = 4 , centre = (1,3)

#### 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 the coordinates of centre and r , the radius

the equation ${\left(x - 1\right)}^{2} + {\left(y - 3\right)}^{2} = 16 \text{ is in this form }$

and by comparison , centre = (1 , 3) and r = 4