Standard form equation of the circle:
[tex](x-a)^2+(y-b)^2=r^2[/tex]
[tex]\text{a and b are the x and y coordinates of the center of the circle; r is a length of a radius}[/tex]
We have:
[tex](x-1)^2+(y-3)^2=9\\\\\text{therefore coordinates of the center of the circle are (1; 3) and a radius is equal 3}[/tex]
