The ancient Babylonians from around 1700 BC used pi = 3.125. The name of the person who calculated that value was not recorded.
the Egyptians
The first theoretical calculation of a value of pi is attributed to the ancient mathematician Archimedes of Syracuse, around 250 BCE. He approximated pi by inscribing and circumscribing polygons around a circle, calculating the perimeters of these polygons to estimate the value of pi between 3.14 and 3.142857. Archimedes' method laid the groundwork for future calculations and understanding of this important mathematical constant.
The ancient Babylonians were one of the first who gave it a value of about 3 but even today we do not know the exact value of pi only that a circle's circumference dividedby its diameter is equal to pi which is an irrational number because it cannot be expressed as a fraction.
3.141592654 rounded by the calculator
pi is currently at 4 million digits
You take the circumference of a circle and divide it by the diameter.
Yes there once was a US state that tried to legislate the value of pi
While there is no fraction form for pi, 22/7 is an approximation of pi that can be used for a rough calculation .
The most accurate calculation of pi is currently estimated to be around 31.4 trillion decimal places. This calculation was achieved using supercomputers and advanced mathematical algorithms. However, for most practical purposes, using pi to just a few decimal places (3.14159) is sufficient.
Archimedes
The most accurate calculation of pi currently is 62.8 trillion digits, achieved by Timothy Mullican in January 2022 using the y-cruncher software. It took over 108 days to complete the calculation.
And what use can you make of so many digits? 10-15 digits are more than enough for any practical calculation. Anyway, search Google for "digits of pi", and you'll get several places where pi is listed to many digits.