* Pi Approximation Day, also see March 14 -- Pi Day

* Pi Day, March 14

* Pi Day, also see July 22 --" Pi Approximation Day "

The ubiquitous nature of makes it one of the most widely known mathematical constants, both inside and outside the scientific community: Several books devoted to it have been published ; the number is celebrated on Pi Day ; and news headlines often contain reports about record-setting calculations of the digits of.

Pi Day is an unofficial holiday commemorating the mathematical constant π ( pi ).

In 2009, the United States House of Representatives supported the designation of Pi Day.

Pi Approximation Day is observed on July 22 ( or 22 / 7 in day / month date format ), since the fraction < sup > 22 </ sup >⁄< sub > 7 </ sub > is a common approximation of π.

The earliest known official or large-scale celebration of Pi Day was organized by Larry Shaw in 1988 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 ( HRES 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.

Pi Day is observed on March 14 because of the date's representation as 3 / 14 in month / day date format.

Pi Approximation Day is therefore observed on July 22.

There are many ways of observing Pi Day.

The Massachusetts Institute of Technology has often mailed its application decision letters to prospective students for delivery on Pi Day.

Starting in 2012, MIT has announced it will post those decisions ( privately ) online on Pi Day at exactly 6: 28pm, which they have called " Tau Time ", to honor the rival numbers Pi and Tau equally.

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.

Pi is used in formulas concerned with the dimensions of circles.

Her husband, who is the son of Alton John Mason of Shreveport, La., and the late Mrs. Henry Cater Parmer, was president of Alpha Tau Omega and a member of Delta Sigma Pi at Lamar Tech, and did graduate work at Rhodes University in Grahamstown, South Africa, on a Rotary Fellowship.

* 1904 – The Pi Kappa Phi Fraternity is founded at the College of Charleston.

Pi Gruis, an optical double with a variable component, is composed of Pi < sup > 1 </ sup > Gruis and Pi < sup > 2 </ sup >.

Pi < sup > 1 </ sup > is a semi-regular red giant with a minimum magnitude of 6. 7 and a maximum magnitude of 5. 4.

Pi < sup > 2 </ sup > is a white giant 132 light-years from Earth and is often brighter than its companion at magnitude 5. 6.

Pi Hydri, composed of Pi < sup > 1 </ sup > Hydri and Pi < sup > 2 </ sup > Hydri, is divisible in binoculars.

Pi < sup > 1 </ sup > is a red star of magnitude 5. 6, 740 light-years from Earth.

Pi < sup > 2 </ sup > is an orange star of magnitude 5. 7, 468 light-years from Earth.

The school is home to six different fraternities: Kappa Alpha Order, Alpha Phi Alpha, Sigma Alpha Epsilon, Pi Kappa Alpha, Lambda Chi Alpha, and Kappa Sigma ; as well as five sororities: Delta Delta Delta, Kappa Delta, Phi Mu, Chi Omega, and Delta Sigma Theta.

* 1868 – The Pi Kappa Alpha Fraternity is founded at the University of Virginia.

* 1907 – Delta Sigma Pi is founded at New York University.

The national honor society for college and university students of government and politics in the United States is Pi Sigma Alpha.

The product operator for the product of a sequence is denoted by the capital Greek letter Pi < span style =" font-family: times, serif ; font-size: 150 %">∏</ span > ( in analogy to the use of the capital Sigma < span style =" font-family: times, serif ; font-size: 150 %">∑</ span > as summation symbol ).

Cao Ren observed that Liu Bei could not have too much control over his new men given by Yuan Shao, and targeted the rebel leader Liu Pi and had him killed in battle ; Liu Bei was subsequently defeated.

Though no extrasolar planets have been observed around Pi < sup > 3 </ sup > Orionis, the star is considered a prime location for planets as small as the Earth.

The title, jointly developed by id and Pi studios, was released on Xbox Live Arcade on December 15, 2010.

In August 2011, the ARM-based Raspberry Pi credit card-sized computer was shown running a specially compiled ARM version of Quake III on the Debian Linux Operating System.

* Cao Pi: A Discourse on Literature

Cao Pi's strategist Liu Ye suggested that Cao Pi decline — and in fact attack Sun Quan on a second front, effectively partitioning Sun's domain with Shu, and then eventually seek to destroy Shu as well.

Cao Pi launched a major attack on Wu, but after Wei defeats in early 223, it became clear that Wu was secure.

In 224 and 225, Cao Pi again made attacks on Wu, but each time the Wu forces were able to repel Wei's with fair ease — so easily that Cao Pi made the comment, " Heaven created the Yangtze to divide the north and south.

There are eight fraternities ( Alpha Kappa Lambda, Delta Sigma Phi, Delta Upsilon, Kappa Sigma, Sigma Alpha Epsilon, Sigma Chi, Sigma Lambda Beta, and Tau Kappa Epsilon ), and four sororities ( Alpha Chi Omega, Alpha Pi Sigma, Alpha Xi Delta, and Alpha Gamma Delta ) on campus.

* Alpha Delta Pi ( ΑΔΠ ), a sorority organization on college campuses

In this proposal, the " dark saying " is a pun on the nursery rhyme Sing a Song of Sixpence, found in “ Four and twenty blackbirds ( dark ) baked in a pie ( Pi )", used to refer to the first twenty-four black notes.

Pi Beta Phi, the first national secret college society of women to be modeled after the Greek-letter fraternities of men, was founded on its campus in 1867.

Students in all five fraternities live in dormitories on campus, following the recent removal of Phi Kappa Pi from Merriman House.

Much of the decisions on important matters of state were entrusted to Wang Pi and Wang Shuwen, both of whom were named imperial scholar and was largely making decisions at the Hanlin Institute.

It was said that Wang Pi was taking a large amount of bribes, and that his house had no closets or regular chests, but a single large chest in which he stored his treasure ; at night, he and his wife would sleep on it.

In summer 805, when the powerful eunuch Ju Wenzhen ( 俱文珍 ) had Wang Shuwen technically promoted — to be the deputy minister of census — but removed from the post of imperial scholar, thus disallowing him from attending to matters of state at Hanlin Institute — Wang Pi interceded with Emperor Shunzong on Wang Shuwen's behalf, and Wang Shuwen was allowed to visit Hanlin Institute once every three to five days.