Pi Day
Pi Day  

Larry Shaw, the organizer of the first Pi Day celebration at the Exploratorium in San Francisco


Significance  3, 1, and 4 are the three most significant figures of π 
Celebrations  Pie eating, discussions about π^{1} 
Date  March 14 
Next time  14 March 2015 
Frequency  annual 
Related to  Pi Approximation Day 
Part of a series of articles on the 
mathematical constant π 

Uses 
Properties 
Value 
People 
History 
In culture 

Related topics 
Pi Day is an annual American celebration commemorating the mathematical constant π (pi). Pi Day is observed on March 14 (or 3/14 in the month/day date format), since 3, 1, and 4 are the first three significant digits of π in decimal form. In 2009, the United States House of Representatives supported the designation of Pi Day.^{2}
Pi Approximation Day is observed on July 22 (or 22/7 in the day/month date format), since the fraction ^{22}⁄_{7} is a common approximation of π.^{3}
History
The earliest known official or largescale celebration of Pi Day was organized by Larry Shaw in 1988 at the San Francisco Exploratorium,^{4} where Shaw worked as a physicist,^{5} with staff and public marching around one of its circular spaces, then consuming fruit pies.^{6} The Exploratorium continues to hold Pi Day celebrations.^{7}
On March 12, 2009, the U.S. House of Representatives passed a nonbinding resolution (HRES 224),^{2} recognizing March 14, 2009 as National Pi Day.^{8}
For Pi Day 2010, Google presented a Google Doodle celebrating the holiday, with the word Google laid over images of circles and pi symbols.^{9}
The entire month of March 2014 (3/14) has been observed by some to be "Pi Month".^{10}^{11}
In the year 2015, Pi Day will have special significance on 3/14/15 at 9:26:53 a.m. and p.m., with the date and time representing the first 10 digits of π.^{12}
Observance
Pi Day has been observed in many ways, including eating pie, throwing pies and discussing the significance of the number π.^{1} Some schools hold competitions as to which student can recall Pi to the highest number of decimal places.^{13}^{14}
The Massachusetts Institute of Technology (MIT) has often mailed its application decision letters to prospective students for delivery on Pi Day.^{15} Starting in 2012, MIT has announced it will post those decisions (privately) online on Pi Day at exactly 6:28 pm, which they have called "Tau Time", to honor the rival numbers Pi and Tau equally.^{16}^{17}
The town of Princeton, New Jersey, hosts numerous events in a combined celebration of Pi Day and Albert Einstein's birthday, which is also March 14.^{18} Einstein lived in Princeton for more than twenty years while working at the Institute for Advanced Study. In addition to pie eating and recitation contests, there is an annual Einstein lookalike contest.^{19}
See also
References
 ^ ^{a} ^{b} Landau, Elizabeth (20100312). "On Pi Day, one number 'reeks of mystery'", CNN. Retrieved on 20100314 from http://www.cnn.com/2010/TECH/03/12/pi.day.math/index.html.
 ^ ^{a} ^{b} United States. Cong. House. Supporting the designation of Pi Day, and for other purposes. 111th Cong. Library of Congress.
 ^ "Pi Approximation Day is celebrated today.". Today In History. Verizon Foundation. Retrieved 20110130.
 ^ Berton, Justin (March 11, 2009). "Any way you slice it, pi's transcendental". San Francisco Chronicle. Retrieved 20110318.
 ^ Jonathan Borwein (10 March 2011). "The infinite appeal of pi". Australian Broadcasting Corporation. Retrieved 20110313.
 ^ Adrian Apollo (March 10, 2007). "A place where learning pi is a piece of cake". The Fresno Bee.
 ^ "Exploratorium 22nd Annual Pi Day". Exploratorium. Retrieved 20110131.
 ^ McCullagh, Declan (March 11, 2009). "National Pi Day? Congress makes it official". Politics and Law (CNET News). Retrieved 20090314.
 ^ "Pi Day". Google Doodles. Google. Retrieved 20121009.
 ^ http://www.popsci.com/article/science/itsnotjustpidayitspimonth
 ^ http://cmns.umd.edu/newsevents/events/1774
 ^ Ro, Sam (March 13, 2014). "March 14, 2015 Will Be A OnceInACentury Thrill For Math Geeks". Business Insider. Retrieved 13 March 2014.
 ^ "Honiton Community College Pi Day  Jazmin Year 9". YouTube. Retrieved 20130722.
 ^ "HCC Celebrate International Pi Day". Honitoncollege.devon.sch.uk. Retrieved 20130722.
 ^ McClan, Erin (March 14, 2007). "Pi fans meet March 14 (3.14, get it?)". msnbc.com. Retrieved 20080124.
 ^ "I have SMASHING news!". MIT Admissions. Retrieved 20120312.
 ^ McGann, Matt. "Pi Day, Tau Time". MIT Admissions. Retrieved 20120318.
 ^ "Princeton Pi Day & Einstein Birthday Party". Princeton Regional Convention and Visitors Bureau. Retrieved 20121227.
 ^ "Princeton Pi Day & Einstein Birthday Party". Princeton Regional Convention and Visitors Bureau. Retrieved 20130314.
External links
Wikimedia Commons has media related to Pi Day. 
 Exploratorium's Pi Day Web Site
 NPR provides a "Pi Rap" audiovideo
 Pi Day
 Pi Day: How to Celebrate 3.14

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