| Pi Day | |
|---|---|
 | |
| Observed by | United States |
| Type | Mathematical |
| Significance | 3, 1, and 4 are the three most significant figures of π in its decimal representation. |
| Celebrations | Pie eating, pi memorization competitions, discussions about π[1] |
| Date | March 14 |
| Next time | March 14, 2025 |
| Frequency | Annual |
| First time | 1988 |
| Related to | Pi Approximation Day |
| Part of a series of articles on the |
| mathematical constant π |
|---|
| 3.1415926535897932384626433... |
| Uses |
| Properties |
| Value |
| People |
| History |
| In culture |
| Related topics |
Pi Day is an annual celebration of the mathematical constant π (pi). Pi Day is observed on March 14 (the 3rd month) since 3, 1, and 4 are the first three significant figures of π, and was first celebrated in the United States.[2][3] It was founded in 1988 by Larry Shaw, an employee of a science museum in San Francisco, the Exploratorium. Celebrations often involve eating pie or holding pi recitation competitions. In 2009, the United States House of Representatives supported the designation of Pi Day.[4] UNESCO's 40th General Conference designated Pi Day as the International Day of Mathematics in November 2019.[5][6]
Other dates when people celebrate pi include Pi Approximation Day on July 22 (22/7 in the day/month format, an approximation of π) and June 28 (6.28, an approximation of 2π or tau).
- ^ Landau, Elizabeth (March 12, 2010). "On Pi Day, one number 'reeks of mystery'". CNN. Retrieved March 14, 2018.
- ^ Bellos, Alex (March 14, 2015). "Pi Day 2015: a sweet treat for maths fans". The Guardian. Retrieved March 14, 2016.
- ^ "Nedräkning mot internationella Pi-dagen". Swedish national radio company (in Swedish). March 14, 2015.
- ^ United States. Cong. House. Supporting the designation of Pi Day, and for other purposes. 111th Cong. Library of Congress Archived August 7, 2009, at the Wayback Machine
- ^ "International Day of Mathematics". UNESCO. March 4, 2020.
- ^ Rousseau, Christiane (September 1, 2019). "International Day of Mathematics" (PDF). Notices of the American Mathematical Society. 66 (8): 1. doi:10.1090/noti1928.