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Although there are measurement techniques that do appropriate pi, that's done mostly because it's interesting. Typically one calculates pi, not measures it. The calculation can't ever be completed but the more you do, the better your approximation. One method is this https://en.m.wikipedia.org/wiki/Leibniz_formula_for_%CF%80

That sort of stuff is done a lot. However, you don't need all that many digits before adding more digits doesn't meaningfully affect calculations. https://www.jpl.nasa.gov/edu/news/2016/3/16/how-many-decimals-of-pi-do-we-really-need/