Finding x from two diagrams?

I've got two diagrams, both made up of two isosceles triangles that touch, with an intersecting line. I have the measurements for their bases, and I know that one of the triangles is the same height in both diagrams (I don't know that value, but it must be equal). I also know that the height of the second triangle in the first diagram is equal to the height of the second triangle in the second diagram, minus a fixed value (that is known, 8,225,000). I need to find the height of the second triangle in the first diagram (x) using the information, but I just cannot work out the equation I need to do this. I've uploaded both diagrams, and a list of all of the values and variables, available here: http://minds-i.co.uk/server/findingX.png

I would really appreciate it if you would be able to shed any light on the solution, or any method you may be able to think of for finding it. Thanks in advance!