As we learned in school, Pi (Greek letter “π”) is the symbol used in mathematics to represent the ratio of the circumference of a circle to its diameter — which is approximately 3.141592653. Okay, personally, I usually remember it's 3.14... something... and rely on the Posse Kid to fill in more digits. However, I remember the two formulas we had to learn way back when:
Circumference of a circle = 2πR
Area of a circle = πR2
Pi is a constant number, meaning that for all circles of any size, Pi will be the same. Pi has been calculated to over one trillion digits beyond its decimal point. As an irrational and transcendental number, it will continue infinitely without repetition or pattern. [copied from www.piday.org] If you want to see the first 100,000 digits, check out Kieker's Pi Day event page GC5KXBF.
Somewhere along the way, someone decided that Pi Day should be celebrated on March 14th (3/14). According to Wikipedia, 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. Pi Day has been observed in many ways, including eating pie, throwing pies and discussing the significance of the number π.
This year is being promoted as "The Pi Day of The Century," because Pi Day will have special significance on 3/14/15 at 9:26:53 a.m. and p.m., with the date and time representing the first 10 digits of π. That same second will also contain a precise instant corresponding to all of the digits of π. Unfortunately, our host establishment wasn't available at 9:26, so we will meet from 11:30 am to 1:30 pm, to eat pie, discuss pi and geocaching, eat a little more pie... Let's have some fun! (But, please, no pie throwing.)
Special Bonus from Groundspeak:
Geek Out with Two New Souvenirs for Pi Day
Just attend an event on Pi Day and you’ll earn the first souvenir. The second souvenir celebrates the mystery of pi—to earn it, log a “Found It” on a Mystery Cache on March 14. http://www.geocaching.com/blog/2015/02/happy-pi-day-earn-two-souvenirs/