Pi Day – A Holiday for Math Geeks

March 14th is Pi Day in the United States. If you have never heard of this holiday, don’t worry, as this is a special holiday observed mostly by math geeks and a few math teachers. Since Pi is usually written as 3.14 and the shorthand in the U.S. for dates is month/day/year or month/day, March 14th becomes 3/14/year making March 14th the day to celebrate Pi – at least math geeks see it this way.

If you think back to grade school or high school when you first encountered the section in math that dealt with the calculation of area – square feet, square miles, etc., you many recall hearing about Pi. For rectangular shapes the calculation was easy, simply multiply the length times the width to get the area. But, when it came to circles the math became more complicated. The formula for calculating the area of a circle is Pi times the radius squared or Area = Pi x R2 where the radius is the distance between the center of the circle to its outer edge (or half the diameter which is defined as a straight line from that passes through the center of the circle from one edge to the other edge). Pi itself is the ratio of the circumference to the radius which, for all circles, works out to be approximately 22/7. When the fraction 22/7 is converted to a decimal by dividing 22 by 7 it comes to 3.141592653589… with the decimal places continuing on forever without ever reaching zero (computers have calculated it out to over a trillion decimal places and still haven’t found the end). Historically, it has only been carried out a few decimal places (3.14 now days and 3.1416 when I was in school) on the theory that the tiny increase in accuracy of measurement was not worth the extra multiplication involved.

Frankly, I have never encountered a situation in my life where I have had to know the area of a circle and I am sure that this is true for most people. For the few who need this, a simple 3.14 times the radius squared is probably sufficient.

In addition to the date in the American format being 3/14, March 14th is also the birth date of Albert Einstein (born March 14, 1879) the brilliant mathematician (of E=mc2 fame) who could explain the mysteries of the universe but could never remember where he left his glasses. It is easy to see how the number combination of the date plus the fact that one of the greatest mathematicians of all time was born on the same date would be a reason for geeks to celebrate.

So, how does one celebrate Pi Day? Like any holiday, this is up to the individual, however, certain customs are beginning to emerge, most of them having a math focus. Like other holidays, there are merchants ready to supply Pi themed decorations for the celebration including Pi T-Shirts, coffee mugs, and jewelry. PiDay.org, which claims to be the official website of the March 14th Pi Day has a shop http://www.piday.org/shop.php on the site that includes these and other momentous for Pi Day. Pies of any kind are great food for this day as their name not only sounds the same, but most pies are round thereby keeping with the circle focus of the holiday. Math games, math trivia, math problems, math jokes, etc., especially ones involving Pi in some manner, are popular activities. WikiHow lists a whole page of activities and ideas for activities. There are also Pi Carols which can be sung. A site called Winternet.com has a page devoted to Pi Day Carols composed by LaVerne Christainson when he was a math teacher at Windom High School in Windom, Minnesota. Since this is a relatively new holiday, even though it celebrates an ancient mathematical formula, there is plenty of room for improvisation as well as a growing number of websites popping up with suggestions. But, like any other holiday, it is a chance for people sharing a common culture (love of math in this case) to get together and have fun.

Pi Day will pass unnoticed by most of us and, unlike other holidays, such as Christmas or Valentine’s Day, it will have no impact on retail sales figures. But, for those who live and breath numbers it is their day to celebrate their life's passion. If you know a math geek, you can wish them well on their special day by sending them a Pi Day e Card. Free Pi Day e Cards are available from PiDay.org, and 123Greetings.com and probably other sites as well.

The March 14th Pi Day date is observed mostly in America, because our short hand for dates is to use numbers in the form of month/day/year. In many other countries the dates are displayed as day/month/year, so the March 14th date is of little significance in these countries. Instead, there are other days that have some connection to Pi and these are dates that are also celebrated as Pi Day or, more accurately, Pi Approximation Day, as the numbers frequently used for Pi are approximations given that the decimals go on for infinity. Other dates on which Pi Day is celebrated in other parts of the world (as well as by some math geeks in the U.S.) are:

April 26th (or April 25 during Leap Years) which is the day on which the distance of the Earth's orbit divided by the time it has traveled is equal to Pi.

July 22nd - using the European day/month notation this day is written as 22 / 7 and 22 divided by 7 gives the 3.14 decimal equivalent of Pi.

November 10th (or November 9th during Leap Years) which is the 314th day of the year.

December 21st at 1:13 p.m. which is the 355th day of the year and the significance of 1:13 p.m. is the fact that the Pi originally calculated in ancient times by the Chinese (ironically about the same time as it was calculated in the West) came out to 355/113. I don't know if they start the party at 1:13 or just celebrate it during the minute the clock is on 1:13.

There are probably other days that also qualify as Pi Day, but, as yet, I haven't found them. However, it is a good thing that this holiday can be celebrated on a number of different days scattered throughout the year. This holiday is not well advertised which makes it easy to forget, especially for math geeks who are so totally focused on their work that they tend to forget things like parties and holidays. Given that approximately half the world either forgets or would forget their wedding anniversary unless their wife reminds them, it is easy to see how it would be easy to forget the unpublicized anniversary of an obscure math formula.