By Tom Barnett

“Probably no symbol in mathematics has evoked as much mystery, romanticism, misconception, and human interest as the number pi (π).”
                —William L. Schaaf, Nature and History of Pi

The Greek letter π was first used for the value 3.1415 in the publication, “Synopsis Palmariorium Mathesios,” written by William Jones in 1706. So, 2006 will be the 300th anniversary of the use of π as a mathematical symbol.

March 14 is an incredible celebration day this year. In the U.S., this date is written 3-14, or 3/14, which uses the first three digits of pi, 3.14. In the international style, this would be written as 14/3, so this is clearly an informal American celebration. A lot of technical writers work with engineers who use a lot of mathematics, and they may be familiar with Pi Day.

The “ultimate” pi day in history occurred on March 14, 1592, at 6:53:59 AM (3/14/1592 6:53:59), which uses the first twelve digits of pi, 3.14159265359 (with the last digit rounded).

The Math

For those interested in the mathematical side of pi, here’s some facts.

• Pi is a constant equal to about 3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209 74944 59230 78164 06286 20899 86280 34825 34211 70679 82148 08651 . . .
   

• Pi is equal to C/2r, where C is the circumference of a circle and r is the radius.
   

• The area of a circle is equal to 2πr, where r is the radius of the circle.
   

• The number of digits of pi needed to calculate the circumference of the universe to within one angstrom* is 35.

Birthdays

Coincidently, March 14 is also the birthday of a famous quantum physicist, Albert Einstein who was born in 1879 in Germany. Some familiar Einstein Quotes include:

Everything should be made as simple as possible, but not simpler.

Reality is merely an illusion, albeit a very persistent one.
The ideas that have lighted my way have been kindness, beauty, and truth.

I never think of the future. It comes soon enough.

March 14 is also the birthday of mathematician you might have heard of: Waclaw Sierpinski (1882). He is famous for the Sierpinski Triangle. See Wikipedia for a description.

And, March 14 has a full moon to celebrate everything happening that day!

* An angstrom is a unit of measure equal to 1 hundred-millionth of a centimeter.