# Zu Chongzhi and PI

http://www.chinese.cn 09:24, November 2, 2009 hwjyw.com

Zu Chongzhi

Zu Chongzhi (429-500 AD) was a famous mathematician, astronomer and mechanic in the Southern and Northern dynasties (421-581 AD). Smart and fond of learning since childhood, he liked natural science, literature and philosophy, and later became a world-famous scientist.

The achievements Zu Chongzhi made in mathematics have been universally acknowledged. He worked out an accurate value of PI. PI is usually represented by , and it has always been a very important yet difficult research topic for mathematics to calculate the value of PI. Many mathematicians of ancient China made painstaking efforts in this research with satisfactory results. Based on earlier research, Zu Chongzhi continued to carry out systematic study. After calculating more than 1,000 times, he concluded that the value of PI falls between 3.1415926 and 3.1415927; and therefore he became the first scientist in the world who calculated the value of PI to seven decimal places. Zu Chongzhi also put forward the thesis that the approximate value of PI was 355/113, which was called milv(close ratio), pushing the calculation of PI to a new stage. The value was the most accurate in the world at that time, and Japanese scientists respectfully called it the "Zu Chongzhi Ratio". Not until more than 1,000 years later, did scientists in the West come up to and surpass the achievements of Zu Chongzhi.