Pi uses the Greek letter π, which is an irrational number, that is, an infinite cycle decimal. In daily life, pi is usually expressed as 3. 14, which is used for approximate calculation.
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.
Extended data:
π = 3. 14 15926 was calculated by Zu Chongzhi, a mathematician in the Northern and Southern Dynasties.
"Secant circle method" is a method of infinitely approaching the area of a circle by using the inscribed area of a regular polygon, that is, finely cutting a circle through the inscribed area of a regular polygon, so that the circumference of a regular polygon can infinitely approach the circumference of a circle, thus obtaining a more accurate pi.
First, the circle is inscribed with a regular hexagon, then the circle is inscribed with a regular hexagon to divide the circumference into six arcs equally, and then each arc is divided into two to make a circle inscribed with a regular dodecagon. The circumference of this regular dodecagon is closer to the circumference than that of a regular hexagon.
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