Many mathematicians have studied pi in history, among which Archimedes, Claudius Ptolemy, Zhang Heng and Zu Chongzhi in Syracuse are famous. They try to calculate the value of pi in their own country by their own methods. The following are the research results of pi around the world.

Asia

China:

In Wei and Jin Dynasties, Liu Hui approached the circumference by increasing the number of sides of a regular polygon (that is, "cyclotomy"), and got the approximate value of π 3. 14 16.

Zhang Heng of Han Dynasty concluded that π divided by the square of 16 equals 5/8, that is, π equals the root of 10 (about 3. 162). Although this value is not accurate, it is easy to understand, so it has been popular in Asia for some time.

Wang Fan (229-267) discovered another value of pi, which is 3. 156, but no one knows how he got it.

In the 5th century, Zu Chongzhi and his son calculated a pi of about 355/ 1 13 with a regular polygon of 24576. Compared with the real value, the error is less than one in eight hundred million. This record was not broken until 1000 years later.

India:

Around 530 AD, the mathematician aryabhata used the perimeter of a 384-sided polygon to calculate the pi of about √9.8684.

Brahma Gupta used another method to derive the square root of pi equal to 10.

Europe

Fibonacci calculated pi as about 3. 14 18.

Vedic Calculations 3. 14 1596535