# All celebrate π Day

Hooray! It’s the day we celebrate the ratio of a circle’s circumference to its diameter. That’s C/d or π or 3.14159 26535 89793 23846…. (and so forth).

Wed, Mar 13, 2013, 22:30

That’s an order. Apart from anything else, you have to respect the various lunatics who devised this fine jamboree for their determination to nod towards the number itself in the date. Thursday March 14th — currently tomorrow; today in a moment or two – is the date on which you must bow down to the ratio of a circle’s circumference to its diameter. Now, unfortunately we really do have to give in to the stupid American date convention here. In Detroit, Denver and De Moines March 14th is abbreviated as 3/14, you see. And, of course, π is, roughly speaking, 3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209 74944 59230 78164 06286 20899. So the date is the first three significant places of that number. If April weren’t one of those stupid months that had only 30 days then we could make a case for the European notation. Alas 31/4 is the calendar’s idea of an imaginary number. So, we’re stuck with it I guess.

e is quite suave. Apéry’s constant deserves a little more attention. But π really is the man. It turns up in so many unusual places. Did you know that  π/4 = 1 – 1/3 + 1/5 – 1/7 + 1/9 -1/11 … (and so on asymptotically). Of course you did. You’re no fool. There’s also a nice approximation involving nested square roots of two that I can’t quite figure out how to represent here. Fans of approximation can celebrate something a little like π on July 22nd. The constant is, you see, nearly equal to 22/7. What Larks, Pip.

Anyway, why not have some of your circle of friends round for a slice of pie. Ha ha! We mathematics fanatics are such fun. Just ask our good friend Darren Aronofsky.