How does pi come about? What is pi used for?

Draw a perfect circle, measure the circumference, diameter.

Perimeter divided by diameter,

Pi is a key value for accurately calculating geometric shapes such as circumference, area of a circle, volume of a sphere, etc.

Pi is represented by the Greek letter (pronounced pài) and is a constant (approximately equal to, representing the ratio of the circumference to the diameter of a circle. It is an irrational number, i.e., an infinite non-cyclic decimal.

In daily life, it is common to approximate the approximate rate of pi. Ten decimal places is sufficient for general calculations. Even the more sophisticated calculations of an engineer or physicist would at best be a few hundred decimal places.

Pi is used to: know the perimeter to find the diameter or the known diameter to find the perimeter, and it has nothing to do with finding the area of the circle.

Since the diameter of the hailstone is 3 units long, the circumference of the curve of the corresponding circle is 6 + 2 3 units long (this is based on the fact that "the area s of the circle is equal to seven times the square of one-third of its diameter d").

For this, pi is derived from the circumference of the circle 6+2 3 divided by the diameter 3.

The ancient Greek Euclid "Geometry Original" (about the beginning of the 3rd century BC) mentioned that pi is a constant of the Ming Dynasty, and the ancient Chinese arithmetic book "Zhou Ji Sutra" (about the 2nd century BC) has a record of "one path and three days", which also believes that pi is a constant. Historically, various approximations of pi have been used, and most of the early ones were obtained through experiments, such as =(4 3) 4 in the ancient Egyptian papyrus (c. 1700 BC). The first person to use the scientific method to find the value of pi was Archimedes, who in "The Measurement of Circles" (3rd century BC) used the circumference of the circle inscribed and inscribed regular polygons to determine the upper and lower bounds of the circumference of the circle, starting from the regular hexagon and doubling it one by one to the regular 96 sides, resulting in (3+(10 71))<3+(1 7)) He pioneered the geometric method (also known as the classical method, or the Archimedes method) for calculating the circumference of the circle and obtained a value accurate to two decimal places.

Since the diameter is 3 units long, the circumference of the curve corresponding to the circle is 6 + 2 3 units long (this is found according to the "area of the circle s is equal to seven times the square of its diameter d").

To match this, pi is derived from the circumference of the circle 6+2 3 divided by the diameter 3.

Since the diameter is 3 units long, the circumference of the curve corresponding to the circle is 6 + 2 3 units long (this is found according to the "area of the circle s is equal to seven times the square of its diameter d").

To match this, pi is derived from the circumference of the circle 6+2 3 divided by the diameter 3.

Pi must first know the "ratio of the circumference to the diameter of the circle" and then according to its only ratio (6+2 3 to 3) to get its ratio as (6+2 3) 3 or (pi is approximately equal to.

As in the case of 1, the regular quadrilateral ratio must first know the "ratio of the circumference of the regular quadrilateral (square) to the diagonal" and then according to its only ratio (which is 4 to 2) in order to obtain its ratio as 2 2 or (the regular quadrilateral ratio is approximately equal to.

2. The regular hexagon must first know the "ratio of the circumference of the regular hexagon to the diagonal", and then according to its only ratio (6 to 2), its ratio is 3 or (the regular hexagon ratio is equal to 3).

In experience, people have found that the circumference of the circle has a constant ratio to the diameter, and this constant is called pi (<> in the West).

So naturally, the circumference of the circle is: <

or <>

Filial piety is <>

is the diameter of the circle, <

is the radius of the circle).

According to the sum of the six points around the periphery of the circle and the overlapping two points with the three root numbers, the comparison with the sum of the three points of the closed diameter of the car.

Since the diameter of the circle is 3a and the corresponding circumference of the curve is (6+2 3)a, the pi is equal to 3/3 (6+2 3).

1. Any number in the universe can be found in the decimal part of pi, including birthdays, bank cards, and a string of numbers written down in your hand.

2 2 2 2 4 4 6 6 8 8 3 3 5 5 7 7 9 9 This is a formula that Wallace found in 1655.

3. At 2:29 p.m. EST on August 14, 2012, the population of the United States rose to 314159265 (314,159,265) people, which is exactly 100 million times that of pi ( ).

The Chinese mathematician Liu Hui used only the approximation of the circle with a regular polygon in the annotation of the Nine Chapters of Arithmetic (263), and also obtained a value accurate to two decimal places, and his method was later called circumcision. He used circumcision until the circle was connected to the 192-sided circle.

Zu Chongzhi, a mathematician in the Northern and Southern Dynasties, further obtained a value accurate to 7 decimal places (about the second half of the 5th century), gave an under-approximation and an excess approximation, and also obtained two approximate fractional values, the density rate of 355 113 and the approximate rate of 22 7. The density rate was not obtained in the West until 1573 by the German Otto, and in 1625 it was published in the work of the Dutch engineer Antonis, which was called the Antonis rate in Europe.

Since the diameter is 3 units long, the circumference of the curve of the corresponding circle is 6+2 3 units long (this is found according to the principle that "the area of a circle s is equal to seven times the square of one-third of its diameter d").

For this, pi is derived from the circumference of the circle 6+2 3 divided by the diameter 3.