By 1870 pi was known to several hundred decimal digits, for something like this calculation where you have other large sources of error Archimedes approximation

By 1870 pi was known to several hundred decimal digits, for something like this calculation where you have other large sources of error Archimedes approximation from 2 millennia earlier would probably be fine. (<1% error) https://en.m.wikipedia.org/wiki/Chronology_of_computation_of_%CF%80 https://en.m.wikipedia.org/wiki/Chronology_of_computation_of...