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.
