Well, actually im not even good in math.
I took the provided numbers an plottet them on a graph.
Then i realized it was not linear, but looking more like a
"1/x" function.
Then i just looked where the "1=1" "elevation" was,
(270)
From that is was just a bit tinkering with the calcualtor.
Not very impresive I suppose.
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More propper would be some regressive approximation Math probably,
but thats stuff for the Math guys here.