I am looking for assistance with a problem that I can find relatively the long way but not by putting in variables. Ill start with all the information to try to build a vivid picture for the problem im trying to solve.

First I have a know distance that I am X-Raying from which is 6 Ft. from the object.

Next I know what the distance it is to the Film from my X-Ray unit which is 9 Ft.

In my X-Ray Image I get distortion or magnification factor (MF) of the item being X-rayed 9/6=1.5 (MF=1.5 from the front of the object to the film)

Next I choose a known item inside the object that I X-Rayed and measure it. I know if the original size of the object is 1", I measure it in the X-Ray it is now 1.25. The MF from the orgin of the X-Ray to the known object has increased to 1.25 x its original size (MF=1.25/1).

My question is, is there an equation that I can use to find the distance of the item from the front of the package if I know the MF of the front of the package is 1.5. and the MF of the item is 1.25.

As it stands now I can find the Distance of the item by dividing the distance of the Film from Xray unit by a random distance of the item (X).

9'/6.5' =MF 1.3846
9'/7' = MF 1.28571
9'/7.2' = MF 1.25