Happy Pi Day!
Today is Pi Day, marked worldwide in celebration of one of the most important mathematical and physical constants. The discovery and unceasing exploration of pi's properties is one of the greatest achievements in human history, indispensible in engineering, chemistry, architecture, civil and space aeronautics and all of the basic sciences.
Pi Day dates from its creation in 1988 by Larry Shaw, a now-retired physicist at the San Francisco Exploratorium. But the Greek letter for pi, TT, adopted for the number for the Greek word for perimeter, was first used in 1707 by Welsh mathematician William Jones.
Pi Day is marked on March 14, taken from the first three digits of pi (3.14). Pi Minute, March 14 at 1:59 a.m. and 1:59 p.m., is derived from pi's first five digits (3.14159). And Pi Second, March 14 at 1:59.26 p.m., from pi's first seven digits.
Pi, crucial in countless fundamental math calculations, notably height and circumference, is an irrational number. This means its value cannot be expressed exactly as a fraction. And that its decimal representation never ends or repeats.
On Pi Day 2004, Daniel Tammet recited pi to 22,514 decimal points. In March 2009, the U.S. House of Representatives passed a resoluton making March 14 National Pi Day.
Worldwide, Pi Day is celebrated with the consumption and throwing of pies. (Though not to make political statements, as protesters now commonly do). One such event, at the University of Waterloo, one of the world's leading universities for math and other pure-science studies, is shown below. The photo was taken on the third floor of the university's Math and Computing Building.
Brainfreeze Puzzles is conducting a 2010 Pi Day Sudoku Contest. The pi-tailored Sudoku grid appears below. For the contest rules, click here.
And edHelper.com has a 41-question pi quiz here, a brain teaser of calculations for determining surface area and volumes of circles, cones, wedges and other geometric forms.