## Happy Pi Day! Find Pi in the Sky

A lovely lemon angel meringue pie in honor of Pi Day. Pi, denoted by the symbol in the photo, has the unique power of stirring an appetite. Credit: Bob King

Happy Pi Day! Pi is one of the few mathematical constants that immediately conjures up thoughts of food. Pies in particular. My wife Linda, inspired by this important day, prepared a lemon angel meringue pie I can’t wait to taste.

The parts of a circle – the encompassing circumference, the radius and diameter, equal to 2x the radius. Pi is the ratio between the circumference and diameter of a circle.

Exactly what is pi? It’s the ratio of the circumference of a circle to its diameter or the number you get when you divide the circumference of any circle by its diameter. It starts with 3.1415 and goes on forever in a never-repeating pattern. Mathematicians call it an infinite decimal. Unlike 3.57 or 7.5, which have a finite number of numbers after the decimal point, pi continues on into infinity. Divide C by D and you’ll never get to the end.

Not that math geeks with computers haven’t tried. By October 2011 two Japanese guys calculated **10 trillion digits** of pi, a world record. Nice work, but still *far* from infinity.

Pi Day happens every March 14 because the calendar date 3/14 is the same as pi’s first three digits. But this year’s pi celebration is an exceptional one. When you add on the last two digits of the year you get 3.1415. As you might guess, this date alignment happens just once a century.

Let’s go further. When the clocks strikes 9:26:53 a.m. and 9:26:53 p.m. today we can add an additional five digits to make 3.141592653. If you find yourself in a bar or pub this evening, see if you —> Read More