Excel 2007 : extracting values from a graph

[daveyc123]

Hi,
I am comparing cumalative % against grain size Φ in an excell scatter graph.

i now need to know the grain size for Φ5%,Φ16%, Φ50%, Φ84%, Φ95%

is there a simple way to get excell to perform this as i am currently reading them off inaccuratley and have a large quantity of graphs to do this on.

I understand that i could if the line was straight through the formula of the line but just thought that excel may produce a better way!

Many thanks
dave

[Andy Pope]

can you post an example of your data and chart?