[tex]x^{2} +(y-4)^2=36 \\equation \ of \ circle : \\ \\ (x-a)^2 + (y-b)^2=r^2\\ \\where\\ \\center \ of \ the \ circle \ is \ (a,b)\\ \\ radius : \ r[/tex]
[tex]a=0, \ \ \ b=4 \\\\ center \ of \ the \ circle \ is \ (0,4)\\\\ radius: \\ r^2=36\\r=\sqrt{36}\\r=6[/tex]
