Happy Square Root Day!

This day is celebrated when both the digits on the day and month are the square root of the last two digits of the year. The last square root day would be April 4, 2016 (4/4/16), and the next will be May 5, 2025 (5/5/25).

So, it looks like we have a while to wait until the next celebration, and maybe we can come up with some related dessert to eat while we celebrate. We’ll need something to hold us over until then.

We all learned about the square root in math class, how it’s the number that when multiplied by itself results in a specified quantity. A number who’s square root is a whole number is a square number.

Easy examples include 2 being the square root of 4, 3 being the square root of 9, 4 being the square root of 16, and the list continues. A more inquisitive mind might ask, where does this come from, what do I use this for, and why do I have to know this?

## Where the Square Root came from

If you’ve ever asked yourself where a math concept comes from and decided to pursue the train of thought, you’ve often found yourself wanting. Any basic concepts have origins so far back no one can pinpoint exactly who came up with the idea or where it started. More advanced concepts have such complicated proofs it feels like you need a doctorate in math just to figure out why it is what the professor says it is.

The square root falls into the previous category. It’s origins trace back as far as 2000 BC. The Babylonians at the time had very effective methods for estimating the square roots of numbers. Moving forward, 9th-century Arab mathematicians referred to a root (not just the square root), by the term jadhr, which the contemporary Europeans translated to radix. This latin word served as the basis for radical.

Other than that, not much is known about the origins of the square root. It’s beginnings were never officially documented, we can only see how it’s we’ve used it over the years.

## What the Square Root helps Us Calculate

Okay, so we don’t know where the concept came from. But what can it help us find out? Well, a lot of things actually.

Starting off with the basics of algebra and geometry, we see that the square root crops up all over the place. It features heavily in the quadratic formula, which is used to find the intercepts on the x-axis of a parabola.

It also finds its way into the Pythagorean theorem when you go to solve for any variable. The Pythagorean theorem is used to find the length of any side of a right triangle given the lengths of the other two.

In statistics, the square root helps calculate z-scores for data points in large groups of data. A z-score helps statisticians determine where a specific data point is affecting the average in some way.

For example, if you’re trying to figure out how well on your diet is going and one day you decided to have a whole pizza, a bag of chips, and a pint of ice cream. You don’t want your whole diet defined by that one day, so if it’s too far above the average for your diet, you remove it. That’s what a z-score helps figure out.

Moving up to calculus, the square root is a major part of the calculations for arc length calculations in both two and three dimensions. The arc length allows people to figure out how long something is when all they have is an equation model of the surface. Imagine trying to measure the back of a chair, when all you have is the computer-generated model of the chair.

## Why do I Have to Know The Square Root?

Well, as it stands, unless you get into a field that involves math, like science or engineering, you don’t need to use the square root. It’s one of those things that you learn in algebra class that you don’t need to use for anything mundane.

Anything that would occur in a day-to-day event, you could measure with whatever happens to be laying around. Unless you happen to be painting a rather oddly shaped triangular wall, I don’t think you’ll have much to worry about.

Sadly, square root day doesn’t happen nearly as often as it’s cousin Pi Day, nor does it come with an easily identifiable dessert to pair with it. We’ll have to work on that between now and May 5, 2025, which should give us plenty of time.

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