Pi Day, the annual celebration of the otherwise inconsequential March 14 (i.e., 3/14), has become a makeshift holiday for the mathematical baked-good homonym. Rounded off, the ratio pi equates to about 3.14. Since it serves as a cornerstone of both geometry and calculus, and though itâ€™s been encountered by the vast majority of the world, itâ€™s likely that few can explain in depth what this number does and why it allows them to eat pie guilt-free once a year.

For those looking to find out the how and why of pi, *The New York Times*â€™ Steven Strogatz broke down how the ratio works and what exactly it means. Itâ€™s an enjoyable, approachable read. Strogatz explains that, at its core, pi allows mathematicians to cut a circle into an infinite number of slices, ostensibly creating a rectangle, in order to find a true measurement of its area and circumference:

What makes the problem difficult is that circles are round.Â If they were made of straight lines, thereâ€™d be no issue.Â Finding the areas of triangles, squares and pentagons is easy.Â But curved shapes like circles are hard.

The key to thinking mathematically about curved shapes is to pretend theyâ€™re made up of lots of little straight pieces. Thatâ€™s not really true, but it works â€¦ as long as you take it to the limit and imagineÂ

infinitelyÂ many pieces, each infinitesimally small.Â Thatâ€™s the crucial idea behind all of calculus.

And while thereâ€™s much more to it than that, *The A.V. Club *has compiled a list of practical uses of pi, to make your Pi Day a little more geometrically correct:

- Order a pie for your office and then try to cut it into an infinite number of slices. Your coworkers will applaud your attempt, and youâ€™ll be covered in the sticky, mathematical goodness of whipped cream all day.
- After the entirety of the pie has been eaten, you can use pi to measure the distance your tongue traveled when you lapped up the remnant crust thatâ€™s remained along the tinâ€™s rim, you filthy glutton.
- When making a decision about which pie to eat, be sure to take the Pythagorean Theorem (aÂ˛ + bÂ˛ = cÂ˛)Â into account.Â â€śAâ€ť serving as the type of pie you choose, â€śBâ€ť being the size, and â€śCâ€ť becoming your total enjoyment of said pie. (Hint: Donâ€™t use funeral pie forÂ â€śA.â€ť Itâ€™s always gross.
*Always*.)