You need to find an equation that fits the data. Is it linear or polynomial
I will give more info based on your answer.

best wishes

--
Bernard V Liengme
www.stfx.ca/people/bliengme
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"azmodeus" wrote in message
...
I have drawn an XYscatter chart connected with smooth lines. I want to get
the corresponding value on X axis at a know value of Y (50%) how can I do
it?
Is it possible to show the calculation by perpendicular dropping lines?