This is the day sweet toothed snackers and pastry enthusiasts wait for every year – Pi Day, or as probably a large percentage of those pie eaters would write it out, and for as much as they care of its significance – Pie Day. Now that opens a whole new line of thought. Exactly what does pi actually do in the real world? And while we’re at it, why pi?

That second question is easier to answer. Everybody, even those insisting on it being Pie Day, knows pi (without the ‘e’) has something to do with math and some of those everybodies might even know it’s most closely associated with circles. Pi is the relationship of a circle’s, any circle’s circumference to its diameter. There’s a great two-minute video here that demonstrates that with a touch of humor and extra pepperoni. Although the concept of pi (again, without the ‘e’) was first demonstrated in the third century B.C., it wasn’t until 1706 on this side of the Common Era dividing line that British mathematician William Jones decided the Greek letter and symbol would make a dandy stand in for 3.14 etc.etc.etc. in calculations. But Leonhard Euler (yes, the is THE Euler) made it popular in his textbooks and justified the Greek Pi, corresponding to P, because pi is all about the perimeter (or circumference) of a circle. (In case you’re wondering, pie (with the ‘e’) has been around since about 6,000 B.C..)

Now the first question isn’t actually hard to answer. It is hard to pin it down to less than a few hundred dozen applications that are possible only because somebody, sometime, somewhere worked out the calculations to make whatever it is work, using pi. These include radio waves that not only make AM radio possible, but blue tooth that is powering those high priced ear buds you have sitting on your desk.  Not straying too far from there, the GPS function of your phone wouldn’t be possible today if some engineer hadn’t tossed pi into an equation or three. And just that you can talk to your phone or home assistant is possible because voice recognition schemes all use pi to calculate and translate vocal waveforms into computerese. But, you ask, what can you do with it?

If you so wanted to, you could use pi to calculate how much water it takes to fill the kid’s backyard swimming pool, how much stain you need to cover the floor of the gazebo, or how much frosting to make to adequately decorate the surprise party birthday cake. Even more practical is determining what size electrical conduit to buy for that remodel you’re DIY-ing, or how much pie filling you need for the deep dish apple pie the kids are expecting after dinner. Yes, I know, there are charts and recipes for all these things. But now you know you could calculate the answer if all the computers in the world suddenly stopped working or worse, decided to take over and not talk to us anymore. Not too far-fetched you know. Didn’t you ever see “Colossus: The Forbin Project?” (Or one not so evil, like EMARAC from “Desk Set.” If the computers are going to take over, that’s the one I want, as long as Ms. Warriner comes with it.)

So now, go off and eat your pie today, today being Pi Day, or Pie Day if you must. And remember, ask not what pi can do for you, ask if you get whipped cream with it!