# The number of Pi

What is the number of pi?
The number pi is a mathematical constant equal to the ratio of the length of a circle to its diameter. It is denoted by the Greek letter «π». It is worth noting that the number of Pi is irrational, due to which its decimal representation never ends and is not periodic.

Besides, Pi is also a transcendental number, that is, it cannot be the root of any polynomial with integer coefficients. An interesting fact is that the proof of the transcendence of Pi has put an end to the attempts to construct the quadrature of the circle, which lasted over 2.5 millennia.

It is well known that this number helped the ancient Egyptians in various calculations. Thus, engineers, for example, could find out the length of the circle (perimeter), knowing its diameter. Curiously enough, at that time people could not calculate the value of this constant exactly.

This is quite different now. Mathematicians are able to determine the value of Pi down to a trillionth of a decimal place. Such advances have been made primarily thanks to supercomputers.

Students first hear about pi in elementary school when they are learning about the circle. They learn from the teacher that no matter what circle they draw, they always get the same number — 3.14 — when they divide its length by its diameter.

History of the emergence of pi
In ancient times, people also sought to build majestic structures. However, in order for them not to collapse and stand for many centuries, engineers had to make the most accurate calculations. Even then, the ancients learned about the existence of a mathematical constant.

Today, there are many papyruses on which our ancestors made calculations about the area of the circle. On them, there is a number with a value of 3.160. Curiously enough, a number close to «Pi» can also be found in other countries:

In ancient India, documents dating back to the 6th century B.C. contain an indication that the number «Pi» is equal to the square root of 10, which is about 3.162;
the ancient Greek scientist Archimedes, who lived in the 3rd century B.C., wrote that the ratio of the length of a circle to its diameter lies between fractions 3 1/7 and 3 10/71, which is 3, 141592;
the Chinese mathematician Zu Chongzhi calculated the same number, but with even greater accuracy, to the 7th decimal place.
The British mathematician William Jones authored the term «pi» himself in 1706.
The term «mathematical constant» became generally accepted in 1737 after the publication of the scientific works of Leonhard Euler.

What is pi?
To date, no one knows the exact number of decimal places in the number of pi. For this reason, many people call this number infinite.

An interesting fact is that modern supercomputers were able to find out 10 trillion digits after the decimal point. Incredibly, no correlation or trend has been detected in this immense number of digits.