Monday, March 14, 2011

Pi day

It is 3.14 today. Happy Pi Day.

Pi is a mathematical constant calculated from the ratio of the length of a circle's rim (its circumference) to its breadth (its diameter). It is perhaps the most well known mathematical term.

Over the years the value of Pi has been refined to the approximate value we use today, 3.14159265, Google says.

An ancient (2000BC) document called the Rhind Papyrus gives Pi the value of 3.16045. The fourteenth century South Indian Mathematician Madhava calculated Pi to thirteen decimal places, or 3.1415926535898.

The ratio of a circle's circumference to its diameter can never be an exact fraction, so Pi is both an irrational number, because it can never be calculated to an exact fraction, and a transcendent number. The more you calculate Pi, the more of Pi there is, and, using computers, Pi has been calculated to 5 trillion decimal places. With the rest of infinity to go, there are concerns that machines will never be fast enough to calculate Pi before the universe ends.

Oh, and for the eleet who care about such things, the number 42 is Pi x 13.37. Roughly.

Enjoy Pi Day.


  1. I've always like the look of π, but never thought about it in date terms. So, pi day has nothing to do with crust and filling :)

  2. If you know how thick a pie is and what size dish you use then π times the square of size times the thickness divided by 4 lets you know how much pie there is.