It’s Pi day today – yes – Pi, not Pie. But if the day inspires you to eat a piece of pie go right ahead!! Pies are circular after all.

We’re not mathematicians! There are some math experts at AMS and we’ll check in with one of them later. But for now, most of us are Pie lovers, not Pi lovers. So what is Pi day, and more importantly… why do we have a Pi day?

Pi is a unit of measurement. Imagine a circle with a line across it. Pi is the ratio of the circumference of that circle to its diameter—a number just a little bit bigger than three. The diameter is twice the radius or double the length from any point on the circle to its center. Got that? The circumference is the distance around a circle.

#### An irrational transcendental number?

We are told that the symbol π has helped scientists understand the universe. When they defined π it inspired a new notion of the measurement of angles. It was a new unit of measurement. What’s kind of mind blowing about Pi is when you do the math, the resulting number is never ending – it just goes on and on!

Here’s a quote from google: *The pi value in fraction is 22/7. It is known that pi is an irrational number which means that the digits after the decimal point are never-ending and being a non-terminating value. Therefore, 22/7 is used for everyday calculations.*

Here’s a little more from Google for us: *If you want to measure its diameter, you could use a normal tape measure wrapped around the object to measure its circumference – that is the distance around the outside of the object, and then calculate the diameter by dividing the circumference by pi.*

So, divide the number by 3.14 or 22/7 as the previous paragraph said. The answer will be an irrational transcendental number? This is too much thinking.

#### Why it matters enough to have a DAY!

According to History.com they chose March 14 as Pi Day because 3.14 represents the first three digits of pi, and it also happens to be Albert Einstein’s birthday. Here is the full story.

*“March 14 marks Pi Day, an annual celebration of the mathematical sign pi. Founded in 1988 by physicist Larry Shaw, March 14 was selected because the numerical date (3.14) represents the first three digits of pi, and it also happens to be Albert Einstein’s birthday.*

*“The first Pi Day celebration took place at the Exploratorium (Shaw’s place of work), a San Francisco-based interactive science museum, and featured a circular parade and the eating of fruit pies. It wasn’t until 2009, however, that it became an official national holiday when the U.S. House of Representatives passed legislation.*

*“Why all the fuss about pi? The Ancient Greek mathematician Archimedes is most commonly credited with being the first to accurately calculate the estimated value of pi. Since it is an irrational, transcendental number, it continues on to infinity—the pi-ssibilities are endless! The seemingly never-ending number needs to be abbreviated for problem solving, and the first three digits (3.14) or the fraction 22/7, are commonly accepted as accurate estimations.*

*“In mathematics, this infinite number is crucial because of what it represents in relation to a circle—it’s the constant ratio of a circle’s circumference to its diameter. Pi is also essential to engineering, making modern construction possible.”*

Essential to Engineering! That’s fairly easy to see, that Pi would be essential to modern engineering and construction. This is a very significant day to lots of folks in our world – thank you Creator for π.

#### What does an AMS ‘math person’ say?

We asked Shannon Crader, our Software Development Manager what Pi day means to her. Shannon said, *“Pi day is so much fun. I love the puns and the completely legit reason to eat pie (cherry, of course)! It’s also a way to create some excitement around math which is typically a somewhat dry subject for kids. Since Pi is the ratio of the circumference of a circle to its diameter, pie and pizza both work to make learning fun on Pi day!*

*“Did you know that there was a Super Pi day? It was celebrated on March 14, 2015. This was because the date was 3/14/15, adding two more digits of pi. The real excitement came two times later that day when the first 10 digits of Pi were represented by including the time: 3/14/15 9:26:53 (am and pm).”*

Shannon concluded, *“One more fun thing for you: If you write the first 3 digits of Pi backwards (3.14), it looks like the word PIE.”*

If you prefer to appreciate pie, well all is not lost. While searching the net we found a lot of places offering free pie on Pi day. Pillsbury has a special pie recipe, for the Pi Pie! It looks like for pizza makers this Pi day is a big annual celebration day!!

So, have some pie today and enjoy the fact that π exists and that the shape of round goes on and on and on… and on.

One more thing from Shannon: “Here is a nifty College Humor song on you-tube that is fun to listen to and watch on Pi day:” LINK