in the xy-plane, the z-component is 0. so use the distance formula to find the distance between (3,7,-5) and (3,7,0)

similarly, for the xz-plane, find the distance between (3,7,-5) and (3,0,-5)

and for the yz-plane, find the distance between (3,7,-5) and (0,7,-5)

this site looks neat. draw your diagram, fill in the required measurements, enter then in the required fields and follow the solution given.

plug in the points, you will get:

take the dot product and simplify to get the form:

the center is (h,k,m) and the radius is R