I have a chart in Excel 2007 and I want to provide a Y value (that is not one
of the data points) and have Excel to tell me the corresponding X value from
the chart. How can I do that?
The chart is not a straight line, so trendline won't work
Here is a picture of the chart I'm working on
http://hkoyda.blu.livefilestore.com/...x_wA/graph.JPG

Any help in this matter would be greatly appreciated.
Yahya