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JohanSund563's avatar
JohanSund563
Copper Contributor
Sep 16, 2021

Find intersection between to lines

Hey! 

I would like to find the point of intersection between to lines in excel. The blue dots are from column D and E and the orange is from column F and G. i have a lot of data and saw another way on the community on how to do it but i cant figure it out in my excel sheet. I am using excel on mac. 

 

1 Reply

  • JoeUser2004's avatar
    JoeUser2004
    Bronze Contributor

    I cannot read the image.  It is too small; and it becomes blurry when I zoom.  It is always better to attach an actual Excel file.

     

    You ask about the intersection of two "lines".  Usually, the word "line" means a straight line.  But to my tired eyes, the blue curve does not appear to be straight.  Am I right?

     

    If yes, would a linear approximation (trendline) of the blue curve be sufficient for your purposes?

     

    If the mathematical formulas for the two (straight) lines are y1 = a1*x + b1 (orange) and y2 = a2*x + b2 (blue), where a1, a2, b1 and b2 are constants and y1 and y2 are names (like "x"), not cell references, they intersect at:

     

    x = (b2 - b1) / (a1 - a2)

    y = a1*x + b1

     

    If you cannot translate the mathematics into Excel formulas for your worksheet, then again, it would behoove you to attach the Excel file.

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