BEIJING, March 13 (Xinhua) -- March 14 is celebrated around the world as Pi Day, since 3, 1, and 4 are the first three significant digits of the mathematical constant which denotes the ratio of a circle's circumference to its diameter.
Even till this day, calculation of Pi, an irrational number, continues with the help of advanced digital technologies and the digits have reached trillions of decimal places. In contrast, mathematicians in the past centuries only had analog tools at hand and an approximate Pi calculation did not come easy.
Zu Chongzhi, a Chinese mathematician and astronomer from the 5th century, had made a remarkable achievement by determining the Pi value with an accuracy of seven decimal places, between 3.1415926 and 3.1415927. His calculation remained the world's most accurate for nearly 1,000 years until the 14th century.
Zu's contributions were recognized and acclaimed worldwide: both a lunar crater and an asteroid bear his name; a high school was named after him in his hometown Laishui in north China; and there are stamps and dramas inspired by him.
Students of the Zu Chongzhi High School stand in a formation of the Greek letter "Pi" during an event commemorating Zu Chongzhi ahead of Pi Day in Laishui County, north China's Hebei Province, March 13, 2021. (Xinhua/Jin Haoyuan)
A statue of Zu Chongzhi is pictured at the Zu Chongzhi High School in Laishui County, north China's Hebei Province, March 13, 2021. (Xinhua/Jin Haoyuan)
A staff member of Hongkong Post shows a special postal stamp set themed on ancient Chinese scientists on Dec. 2, 2015. Zu Chongzhi is featured on the top right corner. (Photo by Wu Yongjian/Xinhua)
File photo shows Lyu Chao, a student from Northwest A&F University, reciting post-decimal Pi values during a Guinness World Record challenge on Nov. 19, 2005. (Xinhua)■
