Question: who gave the most accurate value of pi

title: Pi
text: The first recorded algorithm for rigorously calculating the value of π was a geometrical approach using polygons , devised around 250 BC by the Greek mathematician Archimedes . This polygonal algorithm dominated for over 1,000 years , and as a result π is sometimes referred to as `` Archimedes ' constant '' . Archimedes computed upper and lower bounds of π by drawing a regular hexagon inside and outside a circle , and successively doubling the number of sides until he reached a 96 - sided regular polygon . By calculating the perimeters of these polygons , he proved that 223 / 71 < π < 22 / 7 ( that is 3.1408 < π < 3.1429 ) . Archimedes ' upper bound of 22 / 7 may have led to a widespread popular belief that π is equal to 22 / 7 . Around 150 AD , Greek - Roman scientist Ptolemy , in his Almagest , gave a value for π of 3.1416 , which he may have obtained from Archimedes or from Apollonius of Perga . Mathematicians using polygonal algorithms reached 39 digits of π in 1630 , a record only broken in 1699 when infinite series were used to reach 71 digits . Archimedes