In the school program the big role in mathematics and geometry is given to constants - constants. But very few people can explain from where any given constant appeared. The most known of them is π - number ""p"".
Pi ("π") is the mathematical constant received in quite interesting way. Let's say that diameter a circle is equal to 1 conventional unit. Then the number π is the length of this circle which is approximately equal 3.14 conventional units. Speaking in other words, the number "пи" expresses a ratio between length of a circle and its diameter. This ratio will be always constant.
Pi has a number of properties.
First, the number π is irrational, it means that it cannot be presented in the form of a proper fraction. The value 3.14 is rather approximate, for certain it is not known how many signs after a comma at this constant.
Secondly, number π — transcendental. It means that it can never be degree of any root from other number. Speaking differently, the number π is not algebraic. Moreover, if build any number in degree π, then the transcendental number besides will turn out. It should be noted that ancient mathematicians of Egypt, Greece, Rome, Syria and Iran already knew that the ratio between diameter of a circle and its length is a constant. For example, in Babylon this ratio was estimated as 25/8, and in Egypt as 256/81. But π Archimedes who by a repeated opisyvaniye around a circle and description in it achieved regular polygons enough exact results achieved the greatest progress in calculation of value of number. Archimedes took perimeter of the entered polygon for the minimum value of number π, and described — for maximum. Thus, Archimedes removed value of a constant π, equal 3.142857142857143. It is amusing to note that there is a holiday "Day of Number π\" which is celebrated on March 14. It occurs because if to write down numbers day and date of a holiday, then it will turn out 3.14 — approximate value of this constant. According to other version, this holiday should be celebrated on July 22 as 22/7 is one of the first ratios approximately equal 3.14 too