**Pi Approximation Day** is observed on July 22 (22/7 in the *day/month* format), since the fraction ^{22}⁄_{7} is a common approximation of π, which is accurate to two decimal places and dates from Archimedes.^{}

**Two Pi Day**, also known as **Tau Day**, is lightly observed on June 28 (6/28 in the *month/day* format). ^{}

In 1988, the earliest known official or large-scale celebration of Pi Day was organized by Larry Shaw at the San Francisco Exploratorium,^{} where Shaw worked as a physicist,^{} with staff and public marching around one of its circular spaces, then consuming fruit pies.^{} The Exploratorium continues to hold Pi Day celebrations.^{}

On March 12, 2009, the U.S. House of Representatives passed a non-binding resolution (111 H. Res. 224),^{} recognizing March 14, 2009 as National Pi Day.^{} For Pi Day 2010, Google presented a Google Doodle celebrating the holiday, with the word Google laid over images of circles and pi symbols;^{} and for the 30th anniversary in 2018, it was a Dominique Ansel pie with the circumference divided by its diameter.^{}

The entire month of March 2014 (3/14) was observed by some as "Pi Month".^{}^{} In the year 2015, Pi Day had special significance on 3/14/15 (*month/day/year* date format) at 9:26:53 a.m. and also at p.m., with the date and time representing the first 10 digits of π.^{}

This page was last edited on 21 March 2018, at 01:22.

Reference: https://en.wikipedia.org/wiki/Pi_Day under CC BY-SA license.

Reference: https://en.wikipedia.org/wiki/Pi_Day under CC BY-SA license.

- Mathematical Constant
- Ï (pi)
- March 14
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- United States House Of Representatives
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- Approximation Of Ï
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- San Francisco Exploratorium
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- 111 H. Res. 224
- Google Doodle
- Dominique Ansel
- Circumference
- Diameter

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