The Pi Approximation Day or Casual Pi Day is annually observed across the globe on 22 July to honour and highlight the importance of the mathematical constant Pi, represented using the Greek letter π.
- Pi Approximation Day highlights the significance of Pi in both Mathematics and Physics calculations and the infinite nature of Pi and its real-life applications.
- The Pi Approximation Day was first celebrated at the Chalmers University of Technology, Gothenburg, Sweden.
Why 22 July?
i.When the date 22 July is written in the Day/Month format (22/7), it is viewed as a reference to the fraction 22/7, which is one of the most widely used approximations of Pi.
ii.Pi is an irrational and transcendental number (a decimal with no end and no repeating pattern) most often approximated with the decimal 3.14.
Significance of Pi:
i.π, the symbol used in mathematics to represent a constant is the ratio of the circumference (C) of a circle to its diameter (D) that is independent of the size of the circle.
ii.The value of Pi is approximately 3.14159 but the fraction 22/7 is a common approximation that yields 3.142857….
iii.Archimedes, a Greek mathematician, was the first to use a geometric approach to calculate Pi, suggesting a rational approximation of 22/7 for Pi. Hence, it is sometimes referred to as Archimedes’ constant.
iv.The Greek letter “π” was first used in 1706 by William Jones, a mathematician from Wales, the United Kingdom (UK).
- The symbol π gained popularity after being used by the Swiss mathematician Leonhard Euler in 1737.
Note: The symbol π was chosen because it is the first letter of the Greek word perimetros.
Related Observance:
The Pi Approximation Day, besides being celebrated on 22 July, is also celebrated on 10 November, as it is the 314th day of the year (November 9 in leap years).
- The date is significant for more reasons as well Physicist Albert Einstein was also born on July 22. Theoretical Physicist Stephen Hawking passed away on July 22, 2018.
Pi Day:
i.Pi Day is annually celebrated around the world on 14 March to celebrate the never-ending number, which denotes the Pi value 3.14, when written in the (Month.Date) format in the American calendar system.
ii.Larry Shaw, a staff physicist at the San Francisco Exploratorium, the United States of America (USA), linked March 14 (3.14) with the digits of pi (3.14159…).
- He organised the first-ever known celebration of the Pi Day on 14 March 1988 at the San Francisco Exploratorium, California, the United States of America(USA).
