# Pi Day 2019: Invention, History and Interesting Facts

*Pi Day 2019: Invention, History and Interesting Facts*

Pi Day is celebrated every year on 14 March. This day not only commemorates a very special number but also celebrates the birthday of the great scientist and mathematician Albert Einstein. Let us study more about symbol Pi and Pi day through this article.

**What is Pi?**

In Maths **Pi (π)** is a constant number and is the ratio of a circle's circumference to its diameter. That is for any size of circles the value of Pi will be same. Diameter is the distance of a circle from edge to edge and circumference of a circle is the distance around. Pi is a constant number which is approximately equal to 3.14 or 22/7 and is represented by a Greek letter π.

Do you know that Pi is an irrational number i.e. a real number that cannot be expressed by a simple fraction? According to mathematician pi is also known as infinite decimal which means that after the decimal point, the digits go on forever and ever.

**Pi Day: History**

On 14 March, 1988, first official large-scale celebrations occurred at the San Francisco Exploratorium. This event was organised by Larry Shaw a physicist. Do you know that at this celebration several participants marched around a circle and consumed fruit pies? Years after years it gained popularity and finally the U.S House of Representatives passed HRES 224 on 12 March, 2009, recognising 14 March as Pi Day.

To approximate circles, the mathematician Archimedes used polygons with many sides and determined that Pi was approximately 22/7. In 1706, the Greek symbol π was first used by William Jones. Do you know that a 'p' was chosen for 'perimeter' of circles and so π became popular and was adopted by the Swiss mathematician Leonard Euler in 1737?

**Pi Day: Celebrations**

On this day various celebrations occur worldwide with several activities like people recite Pi and see who can get the furthest. In Museums and Science centers educational programs, music, pi memorisation challenges and math fans celebrate this day by simply enjoying a slice of pie. Numerical fun is also sometimes accompanied by delicious food items like pizza pie, fruit pie etc. As we know that pi is used in formulas in math and physics.

**Some interesting facts about Pi**

- Pi is an irrational number that is it is not possible to calculate Pi by dividing an integer by any other number.

- Pi is a never ending and never-repeating number.

- The symbol of Pi has been in use for about 250 years.

- As value of Pi is never ending so we can't find the true circumference or area of circle.

- In Greek alphabets, Pi is the sixteenth letter and in English also p is sixteenth letter.

- Pi is the ratio of a circle's circumference to its diameter.

- In 19th century, William Shanks calculated the first 707 digits of Pi by hand but unfortunately he made a mistake after 527th place.

- A Japanese scientist, breaking all the previous record, with the help of Hitachi SR 8000 which is a powerful computer found 1.24 trillion digits of Pi.

- Pi is mentioned in Bible.

- In ancient times, Archimedes is the first person who studied about Pi.

- Albert Einstein was born on Pi Day.

- There are no zeros in first 31 digits of Pi.

- Various other names of Pi are Ludolph's Number, Archimedes constant, Circular constant etc.

- In 1706, William Jones introduced the symbol of Pi and was popularised by Leonhard Euler in 1737.

So, now you may have come to know about the mathematics constant symbol Pi.