National Pi Day

Today is 3.14 or National Pi Day. Living in a math and science centric household, obviously, I had to post about this exceptional number.

Ten Pi Facts

1. π represents the relationship between a circle’s diameter and its circumference.
2. The formula to calculate the area of a circle uses pi. A=πr²
3. Pi is an irrational number because its value can not be expressed exactly as a fraction having integers in both its numerator and denominator.
4. Its decimal representation never ends. It also never repeats. At least that is the evidence to date and it has been calculated to more than a trillion places.
5. Pi is also know as Archimedes’ Constant. Archimedes of Syracuse provided an approximation of the number during the 3 century BC.
6. A rarer name is Ludolphine Number. This name is for Ludolphine van Ceulen. He computed a 35-digit approximation around t1600 AD.
7. When π is used as a symbol for the mathematical constant, it is not capitalized at the beginning of a sentence.
8. The capitalized form of pi has a completely different mathematical meaning…the product of a sequence.
9. The earliest known textual evidence of an approximation of pi date from around 1900 BC. Found on both the Egyptian Rhind Papyrus and Babylonian tablets, these approximations are within 1% of the true value.
10. One needs 39 digits of π to make a circle the size of the observable universe accurate to the size of a hydrogen atom.

And let’s not forget the joke: “Pie’s aren’t square, they’re round!”

Interesting side note: On today in 1879, Albert Einstein was born in Württemberg, Germany. He won the Nobel Prize in Physics in 1921