TODAY IS PI Day. You know, March 14. 3/14 is sort of like 3.14. Get it? OK, it's a bit of a stretch because 3/14 looks like a fraction and not Pi. Whatever. We still call it Pi Day.

Even if the date of Pi Day is a little weird, Pi is still pretty awesome. Here are some things you might not know about Pi.

There are many approximations for Pi

If you have a circle, you can measure two things: the distance around the perimeter of the circle (circumference) and the distance across the widest part of the circle (diameter). No matter how big your circle, the ratio of circumference to diameter is the value of Pi. Pi is an irrational number—you can't write it down as a non-infinite decimal. This means you need an approximate value for Pi.