I first became aware of Pi in 2nd or 3rd grade, when there was a banner on our classroom wall showing the first 20 or 30 digits. It said something like “Pi ≈ 3.1415…”. I ask the teacher (though I don’t remember her name, now) what “Pi” was, and was told that it had to do with circles, and that we’d be learning about it later in the year.

When the “Circles Unit” came, we did most of the computation by hand (this was early elementary school) and approximated Pi as 3.14 (or 22/7, if we were “doing fractions”). We learned about the area formula: Pi*r^2 and the circumference formula: Pi*d. Somewhere along the line, I started memorizing the numbers off that banner. To this day, I’ve really never memorized any more than that, though I’ve tried on numerous occasions.

Later on, in Geometry (I think 7th or 8th grade), we started graphing Pi-related things on TI-92s, thus kindling my interest in TI Calculators. We learned formulas for the surface area (4pi*r^2) and volume (4/3*pi*r^3) of a sphere and probably some others. It was about this time that Dan and I started observing Pi Day and registered this domain name.

– Kevin

Zeke Hoskin is a songwriter and retired computer programmer from Bellingham, WA. On March 14, 2008, two of Flip Breskin’s guitar students brought her a pie and explained why. Zeke wrote a song about it, download & listen to the MP3 here.

The Pi Day Challenge is a series of puzzles that are logic based. A team of logicians adapted or created these puzzles – some require research, some require mathematics, some require pure savvy.

TheoremOfTheDay.org’s 2010 Calendar is “12 Theorems by Women Mathematicians”. They also had a special theorem prepared for Pi Day 2009: Download the 2009 PDF.

Urban Threads has released a mathematically marvelous embroidery design to celebrate! “Pi Equals Delicious” will be yummy on creations for math teachers and number-crunching mad scientists of all stripes to celebrate this most circular of holidays.  Check it out.