As New York Times columnist Gary Antonick playfully pointed out this week, 03/14/15 only rolls around once every century, with the full sequential time arriving on 03/14/15 at 9:26:53. The “Pi Day of the Century” has made a significant splash in news media outlets, with the New York Times, PBS, and CBS, among others, reporting.
Why all the irrational celebration?
In 1988, a San Francisco physicist named Larry Shaw designated March 14th as a day to acknowledge and celebrate the irrational number, Pi. In 2009, the United States House of Representatives passed a resolution supporting Shaw’s designation of March 14th as National Pi Day. Since Shaw’s 1988 designation, Pi Day has been celebrated worldwide, and typical festivities range from pie baking and eating competitions to writing Pi poetry and rap. True enthusiasts who wish to celebrate more than once a year often acknowledge Pi Approximation Day on July 22– Archimedes proved, in the 3rd Century BC, that the fraction 22/7 is a close approximation of Pi (an approximation that is still sometimes used by calculators).
Albert Einstein’s (1879–1955) birthday also happens to be March 14th, furthering the cause for celebration in mathematically- and scientifically-minded communities.
A brief history of Pi:
Archimedes’ method for approximating the area of a circle.
The first calculation of pi was done by the ancient Greek mathematician Archimedes (287–212 BC). Archimedes was able to approximate the area a circle, πr², where r is the radius. He accomplished this by drawing a polygon around a circle and inscribing a polygon within the same circle then calculating the areas of each (pictured left). The area of the circle was between these two. Archimedes was able to demonstrate using this method that pi is between 3 1/7 and 3 10/71.
Euclid, & Simson, R. (1829). The Elements of Euclid: Viz, the first six books, together with the eleventh and twelfth ; the errors, by which Theon, or others, have long ago vitiated these books, are corrected, and some of Euclid’s demonstrations are restored ; also the book of Euclid’s data, in like manner corrected. Philadelphia: Desilver.
Later Euclid (323–283 BC) the “father of geometry” was able to prove that the ratio of the area of a circle to the square of its diameter is the same for all circles. This proof appears in Book XII of his Elements.
Highlights from the Library’s collections:
Blatner, D. (1997). The joy of [pi]. New York: Walker and Co..
Posamentier, A. S., & Lehmann, I. (2004). [Pi]: A biography of the world’s most mysterious number. Amherst, N.Y.: Prometheus Books.
Euclid, & Simson, R. (1756). The Elements of Euclid: Viz. the first six books, together with the eleventh and twelfth. In this edition, the errors, by which Theon, or others, have long ago vitiated these books, are corrected, and some of Euclid’s demonstrations restored. Glasgow: Printed by R. and A. Foulis
Want to learn more about Pi? The Library’s math and history of science research guides are an excellent place to start.