Find an equation of the sphere with center (1,-4,3) and

radius 5. What is the intersection of this sphere with the xz-plane?

I know that the equation would be:

$\displaystyle (x-1)^2 + (y+4)^2 + (z-3)^2 = 25$

and the intersection would be

$\displaystyle (x-1)^2 + (z-3)^2 = ?$

but how do you determine the radius of the intersecting circle?

Any help is greatly appreciated