Why Is Today Pi Day?

Why Is Today Pi Day? What Is Pi Short For?
pi, mathematical symbol
March 13, 2014 by: Dictionary.com blog 82 Comments

Today is 3/14, otherwise known as Pi Day – the holiday commemorating the mathematical constant π (pi). Since mathematic notation is a language that uses symbols from a multitude of alphabets and typefaces, it seems only fitting that this sixteenth letter of the Greek alphabet get a little attention.

The Latin name of the Greek letter π is pi, pronounced: pie. The symbol π is derived from the first letter of the Greek word περίμετρος, meaning “periphery,” which refers to the ratio of the perimeter to the diameter – or simply the circumference of a circle. Since pi is an irrational number, it can never repeat when written in decimals. Computers have calculated pi to decimal places in the trillions. It is also a transcendental number, a concept that exceeds the capacity of this post to explain.

In 1689’s “Mathesis enucleata” by J. Christoph Sturm, an “e” is used to denote the equation 3.14159. The first known text to use the symbol π occurred in 1706 with the publication of “Synopsis Palmariorium Mathesios” authored by the English mathematician William Jones.

A piem is a poem that represents π in the way that each word (consisting of letters) represents a digit. Originally introduced by the English physicist, astronomer and mathematician, Sir James Hopwood Jeans, to help mathematicians memorize π, the basic idea consists of the first word containing 3 letters, the second word: 1, the third: 4, the fourth: 1, the fifth: 5, and so on. The following is an example of a piem: ”How I want a drink, alcoholic of course, after the heavy lectures involving quantum mechanics.”

Memorizing a record number of the digits of pi has become somewhat of an obsession. The Guinness World Record for memorizing digits of π is held by a graduate student from China named Lu Chao. It took him 24 hours and 4 minutes to recite the 67,890th decimal place of π without a mistake.