This isn't the kind of thing that Excel has built into it, but it
certainly is capable of the calculations necessary. Do you just have a
table of data or do you have an analytic function [y=f(x)] for the grain
size that you could use to calculate x at y=.6?

If you have the function, then it would be easy enough to solve the
equation for y=.6 either analytically or numerically (using Solver/Goal
seek).

If you don't have the function, you could curve fit the tabulated data
to a reasonable function and then use that to estimate x at y=0.6.

You could also use an interpolation routine (linear interpolation is by
far the easiest to implement) to estimate x at y=0.6. Excel doesn't
have a built in interpolation routine, but you could build one either
with worksheet functions or in VBA.

If all else fails, you could visually pick the value off of the chart.


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MrShorty
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