Can’t Wrap Your Head Around Pi? Here’s a Cool Visual to Help

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 defines the simplest, most perfect shape, the circle. So it’s everywhere around you. Pi is the ratio of the circumference to the diameter of a circle: π = C/d. No matter how big or small a circle is, that ratio is always the same. In decimal notation, it’s 3.141592653 … aaand you can run that out as far as you want, because it’s an irrational number, and it never, ever, ever ends. What people do—in fact what calculators do if you press the π button—is choose a certain number of decimal places, depending on the precision required, and round off to that number. It’s not really pi, but you could say … it’s a piece of pi. (Sorry, but every Pi Day story needs a pi-pun.) Irrational Is as Irrational Does Being infinitely long doesn’t in itself make a number irrational. For example, say you have a r ... Read full article.