The eq (x-9)^2+y^2=484 is of the form
(x-h)^2+(y-k)^2=r^2
Where (h,k) are the coordinates of the centre ofa circle
And r is the radius of the circle.
Now , in this question ,
h=9 and k=0 so coordinates of the centre are (9,0)
And radius is root of 484which is 22