 Archimedes was the first to accurately calculate pi by using polygons with 96 sides both inside and outside a circle then measuring the line segments and finding that pi was between formula_5 and formula_6.A Chinese calculation used polygons with 3,000 sides and calculated pi accurately to five decimal places.The Chinese also found that formula_7 was an accurate estimate of pi to within 6 decimal places and was the most accurate estimate for 1,000 years until arabic numerals were used for arithmetic.