Who estimated pi originally?

Answer 1

There were various estimates of different degrees of accuracy. The ancient Babylonians were content to use pi = 3, although they did know it was an approximation. A Babylonian tablet, dating back to 17th Century BCE gives pi = 25/8 = 3.125 (too small by 0.5%). The Egyptian Rhind Papyrus, of similar antiquity, but claiming to be based on earlier work, estimated pi = 256/81 = 3.16, approx (too large by 0.6%). In the 6th Century BCE, Shatapatha Brahmana used 339/108 = 3.1388... (an error of less than 0.1%).