Pi in Greek letters? π (pronounced pài) is a constant (approximately equal to 3. 14 1592654), which is the ratio of circumference to diameter. It 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 properties:

π 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 satisfaction crime? x？ The smallest positive real number x = 0.

π is an irrational number, that is, it cannot be expressed as the ratio of two integers, which was proved by Swiss scientist johann heinrich lambert in 176 1. In 1882, Lin Deman proved that π is a transcendental number, that is, π cannot be the root of any integer coefficient polynomial.

It is of little practical significance to calculate the value of pi so accurately. A dozen pi values used in modern science and technology are enough. If the value of pi with 39-bit precision is used to calculate the size of the universe, the error is less than the volume of an atom. In the past, people calculated pi to explore whether pi circulated decimals. Since Lambert proved that pi is irrational in 176 1 and Lin Deman proved that pi is transcendental in 1882, the mystery of pi has been uncovered.