### March 14 (3/14) is Pi Day, a day for number lovers like UBC’s Lior Silberman to celebrate the world’s most famous irrational number

Pi Day is an unofficial day to revel in the mystery of the infinitely long mathematical constant that is approximately equal to 3.14. First started in the late ’80s, Pi Day is used by many schools to teach students about the number. MIT sends acceptance letters to prospective students on this day, as well.

Lior Silberman, a professor in UBC’s Dept. of Mathematics, explains the allure of pi.

**When did you first hear about Pi Day?**

I first heard about it was when I went to Harvard University. They take their Pi Day very seriously. They hold pie-eating contests and memorization contests. They run a lot of activities.

**In layman’s terms, what is pi and what is its significance?**

It’s the ratio of the circumference of a circle and the diameter of the circle. So it’s the ratio of having to go across a circle and going all the way around.

It shows up in all sorts of places. Anything that has an arc in it, like a bridge, uses pi. High-pressure tanks are spherical so if you look at their formulas they have pi in them.

**What is the history of pi?**

We knew various cultures had thought about it. The ancient Babylonians and Chinese knew about pi, they knew about the ratio and had some approximate value. The Greeks tried to calculate pi very precisely. Archimedes came up with a method to do this.

There’s a famous sentence in the Bible where Solomon is building his temple and he builds a large bowl that is 10 cubits across and 30 cubits around, which tells you that whoever wrote this text knew that the ratio is around three.

**Is one of the appeals of pi that it is infinite?**

Formally speaking, all numbers are infinitely long. Also, I can create a number that has any patterns I like. What makes pi interesting is that it is naturally occurring, so to speak. Pi wasn’t created by me. Pi is just there.

There’s a question about whether mathematics is something you invent or something you discover. Pi is one of things that feels like it exists independently of mathematicians. It’s there even if humans didn’t know about it.

The number shows we’re not done understanding mathematics. For instance, we believe any sequence of numbers—say, your phone number or something like that—will eventually occur in pi but we don’t know how to prove it.