# Pi Day of the century marks a mathematical marvel

Saturday is Pi Day.

But not just any Pi Day.

It’s the mother of all Pi Days. Pi Day of the Century.

It’s 3-14-15 – as any good geek knows, a date that corresponds with 3.1415, the first five digits of the infinite number pi. That calendar coincidence has math fans practically wriggling with glee, not to mention those who just appreciate the whimsy of celebrating a number that sounds like pastry.

You might say that’s irrational. Mathematicians would agree.

And therein lies the delight of Pi Day.

You probably remember pi from grade school, but here’s a quick refresher: Pi is the number that approximates the ratio of a circle’s circumference to its diameter. In other words, if you divide the circumference of any circle by its diameter, you always get pi, an irrational number that starts with 3.1415 and goes on forever. It shares its name with the 16th letter of the Greek alphabet.

The idea of celebrating Pi Day on March 14 – coincidentally, Albert Einstein’s birthday – started in the 1980s. The first large-scale celebration was organized in 1988 at the Exploratorium museum in San Francisco, and Pi Day got a boost two decades later when the U.S. House of Representatives passed a resolution supporting its celebration in 2009.

“It’s mind-blowing to think about a number that’s infinite and non-repeating,” said Dante Centuori, director of creative productions at Cleveland’s Great Lakes Science Center. Some just couldn’t wait for the big day. The members of the Undergraduate Mathematics Club at Kent State University celebrated at its biweekly meeting earlier this week with activities that included a talk on the history of pi, a debate on the merits of pi vs. tau (that’s 2 times pi, for you English majors) and a beauty contest comparing the complexity of the various fractions and formulas used to approximate pi.

Club secretary Courtney Augustine said before the meeting that the members would also be guessing the circumference of the pizzas being served.

Who said math can’t be fun?

Some online resources to celebrate Pi Day.

Pi calculated to 10 million digits: http://pi.karmona.com.

Pi poem: www.pi314.net/eng/poemes. A poem created from words that are the same lengths as the first 740 digits of pi.

A Piece of Pi: http://tinyurl.com/pieceofpi. Violin composition created by assigning musical notes to numbers and substituting those notes for the digits of pi to 220 decimal places.

Pi rap: http://tinyurl.com/pirapvideo.

Pi search: www.angio.net/pi. Search for a birthday, phone number of any other string of numbers to find out whether and where it occurs in pi.