Overview

Pi Day is an international holiday observed annually in celebration of the Pi (π), the ratio of a circle's circumference to its diameter and one of the most well-known mathematical constants typically approximated as 3.14159, which corresponds to the calendar date March 14th in its numeric format (3/14). Online, the Pi Day is widely celebrated through discussions, homophonic wordplays, such as throwing or eating baked pies, and other creative interpretations of the irrational number.

Background

The earliest known celebration of the Pi Day was organized on March 14th, 1988 by American physicist Larry Shaw, who was then working at the San Francisco Exploratorium^[3], with staff scientists and visitors partaking in a symbolic march around one of its circular spaces and eating fruit pies afterwards. In addition, because the holiday coincides with the birthday of the famed theoretical physicist Albert Einstein, the day has grown into a general celebration of math and science.

Developments

• On March 12th, 2009, the United States House of Representatives passed the bill HRES 224^[6], a non-binding resolution which officially designates March 14th as the National Pi Day.

• On March 14th, 2010, Google celebrated Pi Day by displaying a commemorative Google Doodle with the company's name superimposed over images of circles and π symbols
  on its search homepage in honor of the holiday.

• On March 14th, 2012, the admissions office at the Massachusetts Institute of Technology (MIT)^[9] began sending its response letters to the applicants on Pi Day at 6:28 p.m. (EST) in dual observance of the Pi (π) and Tau (τ), the latter of which represents the time constant (τ = 6.283185) in physics and engineering.

MIT Regular Action admissions decisions will be available online on Wednesday, March 14, beginning at 6:28 PM ET. When decisions are released, access decisions.mit.edu and log in using the same username and password that you use to log into your MyMIT account. There are no interim screens, so you should be sure you are ready to receive your decision online before logging in to decisions.mit.edu. To ensure that you will receive a decision online, please visit https://decisions.mit.edu/verify.php and enter your username and password. The verify page is available now for applicants to confirm their login ability and decision eligibility. If you've forgotten your MyMIT username and/or password, you may use our automated system to reset it. Visit MyMIT and click on the lost username or password links beneath the log-in box on the right.

• On March 1st, 2014, many educational institutions and scientific publications declared the entire month of March as "Pi Month," as the month-and-year calendar format for the year of 2014 also matched up as 3/14, in addition to its alignment with the date-and-month calendar format.

• On March 14th, 2015, many observers of Pi Day paid a special tribute to the holiday at 9:26:53 a.m. and 9:26:53 p.m., as the date-year-time format of those two precise moments represented the first ten digits of π (3.141592653).

Highlights

Fandom

Pi Approximation Day

In addition to the annual observance of Pi Day on March 14th, some mathematicians and academic communities also celebrate Pi Approximation Day on July 22nd in honor of the fraction 22/7, which has been used as a common approximation of π since its introduction by Ancient Greek mathematician Archimedes.

Search Interest

External References