This coming Friday, March 14th, is “Pi Day.” Or as it is known in Greek, Ides of March Eve (one more day to beware!). To explain the origins, customs, and geometric deliciousness of this mathemagical day, I present to you a primer in Socratic method-esque, question and answer format. So sit down, read, and enjoy. And to any Socrates enthusiasts, BYO hemlock-infused punch.
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So what is this “Pi Day” all the kids are talking about?
Actually it’s pronounced “π” not Pi.
Sorry, what is this “π day” all the kids are talking about?
I’m glad you asked. This π dayor “pi day” for the sake of the non-Greek speakers among usis an annual celebration of the mathematical constant “pi.” This constant is 3.14, so Pi Day is held every March 14th: 3/14.
What about those countries in Europe where they write the days as month/day/year? Without a 14th month how do they celebrate Pi Day?
They use the metric system so pi doesn’t apply to them.
OK so Pi is 3.14. Big deal. What’s so important about pi anyway?
What’s so important about pi?! It’s one of the most important numbers in mathematics! Have you ever measured the area of a circle? Or calculated its circumference?
I think so. Maybe a few times in grammar school. And once last week by accident.
Well you wouldn’t have been able to do that without the magic of pi. Back in the old days before pi was invented, people had no way to accurately calculate the circumference or area of a circle.
Let’s say you owned a wheelbarrow business in ancient Greece and needed to know how large a circular wheel you should build for your latest “non-square wheel” model. Since there was no pi you couldn’t calculate this on your own, so you had to visit an oracle to get an estimate. Since oracles always overcharge for wheel circumference estimates, next thing you know you’re flat broke after being price gouged by oracles left and right, your wife left you for an architect who worked strictly in rectangles, and without tuition for school your children fell in with a gang of Zeno followers who sit around all day going nowhere.
Enter pi. Pi is the ratio of the circumference of a circle to its diameter. And not just a circleany circle. No matter how big, how small, or how Euclidian, or the circle is, the ratio of its circumference to its diameter is always 3.14. Now to figure out the circumference of your wheelbarrow’s wheel you just need to take pi and multiply it by the radius, and then that by 2. C=2πr. Done and done.
Isn’t 2r the same as the diameter? Wouldn’t it be easier to just calculate the circumference by multiplying π by the diameter?
Wouldn’t it be easier for you to sit quietly and listen.
Sorry. Duly noted. That pi sure is amazing though! I never knew three numbers could be so important!
Actually saying pi is three numbers isn’t entirely correct. 3.14 is pi rounded to the hundredth and is what most people use for pi. To be exact, pi is 3.14159….and goes on for an infinite number of decimal places after that.
Pi isn’t exactly 3.14? I don’t believe in anything anymore! I quit math and am going to law school!*
Easy there. I apologize if I misled you. It’s just that virtually everyone uses 3.14 as pi. Though of course there are some pi enthusiasts who have memorized it way past the hundredth.
Really? What are the most decimal places anyone has ever memorized of pi?
The 17th century German mathematician Gottfried Leibniz was the first to ever memorize pi to infinity decimal places. Not to be outdone, his contemporary Sir Isaac Newton memorized pi to infinity plus one decimal places. Newton’s record stood for centuries until the early 20th century when a child prodigy in a remote Amazonian village was discovered who had memorized pi to infinity times infinity decimal places. Or so legend has it.
Ok now that I understand pi, what about Pi Day? When did Pi Day start?
The origins of Pi Day are a hotly contested topic amongst historians. Some say that they couldnt care less about Pi Day because it has to do with math, while other historians say theyd like to know but are really not good with numbers. Several mathematicians have published books on the origins of pi day, but as multi-volumed tomes filled with endless strings of 0s and 1s, no one has been able to get beyond the foreword without punching an abacus.
What do you do at Pi Day celebrations?
Eat a bunch of pies, buy T-shirts with clever math jokes on them like “√-1 2^3 ∑ π and it was delicious!” for exactly three dollars and fourteen cents, and have awkward social interactions with the few females in attendance.
Wow, I can’t wait for Pi Day! Are there any other math-based holidays?
Well theres Infinity Day, but Id skip that one since the celebrations seem to go on forever. Theres i Day but most people dont observe that since its a silly, made-up holiday. And then theres Factorial Day where people run around yelling at each other.
Gee, Factorial Day sounds great!
Thats the spirit, Timmie!
My name isnt Timmie, Dad. Its Steve.