For those of you who don't know what I'm referring to, today is March 14. Or, in one particular date notation, it is 3-14! If you want to be even more precise, you could have REALLY celebrated early this morning, at 3-14 1:59:26!
In honor of the annual Pi Day in mathematics, I thought that I would dedicate a brief post to one of the most common irrational constants in all of mathematics: π!
π is a ratio between a circle's circumference and diameter. It is a constant for all circles, regardless of their size. You are probably familiar with these common π-containing equations:
C = πd
C = 2πr
A = πr2
It is an irrational number, meaning that it cannot be expressed by dividing one integer by another integer. So, π cannot be expressed as a fraction. As a result, many aficionados in mathematics pride themselves on being able to memorize π to many, many decimal places. In fact, π has been calculated up to more than a trillion decimal places! You can view the first million decimal places at websites such as piday.org, though since it is irrational, the number of decimals continues infinitely!
In a fun website I just found, I recommend you give a read to 50 Interesting Facts about pi. If you would like to learn more about the history of π and how it was first estimated, the wikipedia page for π also has a lot of historical information, from early methods of estimation by Archimedes all the way through to present-day computer approaches to calculating everyone's favorite constant, π!