Happy Pi Day

Today is Pi Day. 3.14

Pi is the ratio of the circumference of a circle to its diameter. The number is always the same regardless of the size of the circle. While the first people to recognize this ratio is lost to history, there is evidence that this relationship was known over 4000 years ago by the ancient Babylonians. Archimedes made the first best attempt to calculate the value of pi using polygons and the Pythagorean Theorem. Pi is an irrational number. That is, it cannot be expresses by a common fraction and the decimal never settles into a repetitive pattern. Modern computers have calculated the value out to over one trillion decimal places and have not seen a repeating pattern. The Greek letter, Pi, was first used to represent the number in the 1700s. I use the Engineer's Cheer to remember the value of Pi:

e to the x
e to the x
e to the x, dx
cosine, secant, tangent, sine
3.14159