Quote Originally Posted by Megahertz View Post
Robert, I want them to be as accurate as practically possible. Of course I understand there is always a slight margin of error but lets see how this one goes. I knew that you can put formulas in Excel and get values but didn't knew that by putting values one can come up with formulas as well, so could you please explain more how to do it.

Very easy . Using data from your table and the column for Length = 13.85m,


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First, plot the data as a X-Y graph. Then goto Charts -> Add Trendline. I chose a second degree polynomial for the approximation since it's clearly not a stright line. R^2=0.9993 refers to how close to been perfect is the line fitting approximation (R^2=1 is perfect).

Robert