π ≈ 3.141 592 653 589 793 238 462 643 383 279 502 884 197 169 399 375 (Photo: Richard Dombek, Shutterstock)

Today, March 14, the world celebrates one of the most unusual holidays - **International Pi Day** (International π Day).

The Day was first celebrated in 1988 at the San Francisco Exploratorium, a popular science museum in San Francisco, and this unofficial holiday was invented a year earlier by San Francisco physicist Larry Shaw, who noticed that the American date system (month / number) the day of March 14 - 3/14 - coincides with the first digits of the number π = 3.14.

We encounter this unusual number already in the lower grades of the school, when we begin to study the circle and circle. **The number π is a mathematical constant expressing the ratio of the circumference of a circle to the length of its diameter.** In numerical terms, π begins as 3.141592. and has infinite mathematical duration.

In everyday computing, we use simplified spelling of the number, leaving only two decimal places, - 3.14. Looking at this sign, it immediately becomes obvious why it is today that Pi Day is celebrated.

According to experts, **this number was discovered by Babylonian magicians.** It was used in the construction of the famous Tower of Babel. However, an insufficiently accurate calculation of the value of “Pi” led to the collapse of the entire project. It is possible that this mathematical constant was the basis of the construction of the legendary Temple of King Solomon.

It is noteworthy that the International Day of Pi, coincidentally or intentionally, coincides with the birthday of one of the most prominent physicists of our time - the birthday of Albert Einstein.

Scientists and mathematics lovers love this holiday very much, noting it with a variety of physical, mathematical and culinary (!) Events. Cooking here comes in very handy - usually large round cakes are baked, and the whole team sits around a “magic” circle (usually with a drawn “Pi” in the center), treating themselves and discussing the relativity of this unusual number.

Other holidays in the section "International holidays"

## How to celebrate Pi Day with friends?

But nothing complicated! Plan a pajama party or tell your friends that everyone should come in jackets. Decorate the room with numbers Pi made of paper, foil, fruits and flowers, pyramids and Leaning towers of Pisa from sweets. Treat your friends with beer and pizza. According to American tradition, put on the table a large pie with the number Pi and many small cakes for every taste. Serve a variety of pickles for strong drinks - miniature pickled cucumbers, cherry tomatoes, young corn cobs, etc. Refined people will enjoy the taste of pin colada - a cocktail of coconut milk, rum and pineapple juice.

And when your friends have finished feasting, entertain them with mathematical puzzles. Just do not choose difficult tasks if your guests are not part of the scientific fraternity. For example (answers - diameter, point, cone):

For memory of an unusual party, give friends mugs or key rings with the number Pi. Or such t-shirts (by the way, as a dress code - that’s it):

**Interesting pi-facts:**

- World Pi Day (by chance?) coincides with the birth date of the great Albert Einstein,

- the symbol π is the initial letter of the word "περιφέρεια" (a circle in ancient Greek). For the first time, this designation of a value equal to the ratio of the circumference of a circle to the length of its diameter was used by the British mathematician Jones William in 1706,

- the number Pi is infinite, irrational, and never ends. This was already known in 1761. When the infinity of pi became a fact, scientists stopped racking their brains over the quadrature of the circle, recognizing that the task is unsolvable (it is impossible to draw a square equal in area to the circumference using only compasses and a ruler). And the infinity pi means that it is impossible to accurately calculate the area of a circle,

- even the ancient Greek geometers found that the ratio of the circumference of a circle to its diameter is the same for absolutely any circle. But at that time, the number pi was taken as the number 3. In subsequent years, and until our time, scientists constantly “extend” pi, calculating more and more decimal places. In 2010, it was possible to calculate 10 trillion digits after a single decimal point!

- in 2006, Chinese Liu Chao set a new world record for reproducing aloud the number pi, naming 67.890 digits after the decimal point. Chao spent a little more than a day on such a strange monologue!