Originally defined as the ratio between the circumference of a circle and its diameter, pi — written as the Greek letter π — ...

Happy Pi Day! We celebrate pi on March 14 because 3-14 gives the first three digits of this famous number. But what’s the big deal about pi anyway? Why does it get a day? Well, for starters, it ...

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Originally defined as the ratio between the circumference of a circle and its diameter, pi — ...