Pi is the ratio of the circumference to the diameter of a circle, which is generally expressed by the Greek letter π and is a universal mathematical constant in mathematics and physics. π is also equal to the ratio of the area of a circle to the square of its radius. Accurate calculation of geometric shapes such as circle perimeter, circle area and sphere volume is the key value. In the analysis, π can be strictly defined as the smallest positive real number x satisfying sinx = 0.

π = 3.1415926535897932384626 π is an infinite acyclic decimal with an approximate value of 22/7 (approximate rate) and 355/13 (secret rate).

Extended data

Zu Chongzhi, a mathematician in the Southern Dynasties, calculated the approximate value of pi between 3. 14 15926 and 3. 14 15927. He is the first person in the world to calculate pi to seven decimal places. For the convenience of application, the π value is usually only 3. 14 16.

"Sui Shu Law": "Ancient nine numbers, π three, π one, their skills are sparse; Since Liu Xin, Zhang Heng, Liu Hui, Wang Fan and Pi Yanzong, everyone has created new speeds ... Zu Chongzhi has opened a more secret method, with a circle diameter of 100 million as ten feet and a circle of three feet, one foot, four inches, one minute, five minutes, two seconds and seven seconds. "

Couplet back method

Learn a period of literature, have fun, and you will have peace and eternal life.

Only when Philip Burkart thinks small can people speak forcefully.

The number of strokes is decimal places.

References:

Baidu Encyclopedia-π