pi(π):3. 14 159 26535 89793 23846 2643383279 50288 4 197 16939375 10？ 58209 74944 59230 78 164 06286? 20899 86280 34825 342 1 1 70679? 82 148 0865 1 32823 06647 0938446095 50582 23 172 53594 08 128 48 1 1 1 74502 84 102 70 / Kloc-0/93 852 1654 38+0 ... (about equal to 3. 14 1592654), and the value of π is usually expressed by 3. 14.
The fractional part 3. 14 1592654 is enough for general calculation. Even if engineers or physicists want to make more accurate calculations, they only need to take the values to a few hundred decimal places at best.
Pi () is generally defined as the ratio of the circumference () to the diameter () of a circle, or directly defined as the half circumference of a unit circle. According to the properties of similar graphs, the value of is the same for any circle, so a constant is defined.
Extended data
As an ancient geometric kingdom, ancient Greece made great contributions to pi. Archimedes (287–2 BC12), a great mathematician in ancient Greece, initiated the theoretical calculation of the approximate value of pi in human history. Starting from the unit circle, Archimedes first found that the lower bound of pi was 3 by inscribed regular hexagon, and then found that the upper bound of pi was less than 4 by pythagorean theorem.
Then, he doubled the number of sides of inscribed regular hexagon and circumscribed regular hexagon to inscribed regular hexagon 12 and circumscribed regular hexagon 12 respectively, and then improved the upper and lower bounds of pi with the help of Pythagorean theorem. He gradually doubled the number of sides inscribed with regular polygons and circumscribed with regular polygons until inscribed with regular polygons and circumscribed with regular polygons.
Finally, he found that the upper and lower bounds of pi were 223/7 1 and 22/7, respectively, and took their average value of 3. 14 185 1 as the approximate value of pi. Archimedes used the concepts of iterative algorithm and bilateral numerical approximation, which is the originator of computational mathematics.
References:
Baidu Encyclopedia-π