# Author: qdtstaging

[block:qdt_book=qdt_book] Have you ever thought about how it’s kind of weird that a circle has 360 degrees? At first thought, it seems like a rather random number to have chosen—why not 100, or 500, or 720 degrees? Was it really a random choice? Or was there actually some good reason that 360 was chosen to be the number of divisions in a circle? As we’ll find out today, there was indeed a good reason. What was it? We’re not entirely sure. But we do have some pretty good ideas. And those ideas are exactly what we’re going to be talking…

By the end of the last episode, we had proven that the interior angles of a triangle always add up to 180 degrees. Or so it seemed. At the very end, I challenged you to try your hand at a project with a balloon that hopefully forced you to question this conclusion. Did you take me up on that challenge and try the project? If not, it’s not too late to give it a try. And you definitely should since it will force you to think about questions like “How many degrees are in a triangle?” and “Do parallel lines…

You know how the angles of a triangle always add up to 1800? Why is that? After all, 1800 is the angle that stretches from one side of a straight line to another—so it’s kind of weird that that’s the number of degrees in the angles of a triangle. What in the world does a triangle have to do with a single straight line? As it turns out, quite a lot. And triangles also have a lot to do with rectangles, pentagons, hexagons, and the whole family of multi-sided shapes known as polygons. We’ll see exactly what I mean by this…

A few weeks ago, I realized that I have pretty much zero intuition about how much a gram weighs. I know—kind of tragic, right? Nope, not tragic at all. In fact, I see it as an opportunity, because whenever I stumble upon something like this that I don’t know, I’m a fan of figuring it out. So, if you’re at all like me and are not exactly sure just how heavy grams, ounces, pounds, stones, and tons are, then you’re in luck! Because that’s exactly what we’ll be talking about today. Sponsor: Visit GoDaddy.com to get the right domain for…

[block:qdt_book=qdt_book] Quick, what’s 1 + 1? It’s obviously 2, right? Not so fast! What if I was to tell you that I could prove that 1 + 1 is actually equal to 1. And that, therefore, 2 is equal to 1. Would you think I was kind of nuts? More like completely nuts? Probably. But nuts or not, these are exactly the things we’ll be talking about today. Of course, there will be a trick involved because 1 + 1 is certainly equal to 2…thank goodness! And, as it turns out, that trick is related to a very interesting fact…

Happy Vernal Equinox! Spring is just around the corner for most of the northern hemisphere, and with that comes the promise of long and gloriously toasty summer days. If the chill of winter is still in the air where you live, you might be wondering how much longer it’ll be until those longer days arrive. So, how many extra minutes of sunshine are we gaining each day? And, now that I’ve mentioned it, why does the number of daylight hours change throughout the year in the first place? What exactly does that change look like? And what does all of…

Do you know what two angles living inside the same right triangle said to each other? The first angle goes, “Hey Thelma (or is it Theta?), I don’t mean to go off on a tangent here, but what’s your sine?” To which the second angle replies, “Phil (or is it Phi?), I don’t know why you even bother to ask, my sine is obviously the same as your cosine!” Okay, so maybe that’s not the best joke in the world, but once you understand sines and cosines, it is kind of funny. Of course, that means that if you don’t…

[block:qdt_book=qdt_book] After our 3 frequently asked questions about math puzzles episode last week, math fan Cynthia wrote to tell me about one of her favorite puzzles. As luck would have it, Cynthia’s puzzle is based upon one of the same ideas that—as we’ll soon find out—makes our as-yet-unexplained third-and-final puzzle from last time tick. What’s the tie-in between the two? As we’ll see, they’re both based upon some pretty amazing properties of the mysterious and sometimes seemingly magical number 9. How does it all work? And what makes the number 9 so “magical?” Those are exactly the questions we’ll be…

If you’re anything like me, you don’t exactly love doing long division. Which is exactly why I avoid it as much as I can. Of course, one way to avoid doing division the old fashioned way with paper and pen is by using a calculator. Most of the time, that’s exactly what I do. But the truth is that sometimes calculators—or phones with calculators—are inconvenient. And sometimes you need to do division right there on the spot in your head. How can you do it? Keep on reading to learn 5 simple things that you can do to take your…

The numbers we use in our daily lives can be broken up into two main groups: rational and irrational numbers. Irrational numbers cannot be written out exactly in decimal form since you’d need an infinite number of decimal digits to do so. Rational numbers can be written as decimal numbers that either stop after some number of digits or keep repeating some pattern of digits forever. In today’s article, we’re going to learn how to take a decimal representation of a rational number and turn it into an equivalent fraction. What are Terminating and Repeating Decimals? Before we get into…