(This year only!)
Posted on December 16, 2020
Today is one of the mathematical holidays. Like Pi Day, Square Root Day, e-Day, Fibonacci Day, and Pi Approximation Day, Pythagorean Theorem Day occurs when the date fits the mathematical topic. In this case, 12/16/20 (or, in most of the world, 16.12.20) fits with the Pythagorean Theorem.
Um…okay, you say.
But what the heck is the Pythagorean Theorem???
An ancient Greek philosopher named Pythagoras has commonly been credited with discovering – among other mathematical truths – the fact that the “legs” and the “hypotenuse” of a right triangle have a particular mathematical relationship with one another.
You might already know that a right triangle is a triangle that has one square (90 degree) angle. The two sides of the triangle that emerge from that square angle are called the legs of the right triangle, and the last side of the right triangle – which is always the longest side – is called the hypotenuse.
The mathematical relationship between the two legs and the hypotenuse is that, if you square the lengths of Leg A and Leg B, and then add those two squares together, the answer will be the square of the length of the hypotenuse.
In other words:
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| Do you see how this diagram shows you one way of visualizing A squared, B squared, and C squared? |
You may be wondering what square angles and right triangles have to do with December 16, but think of it this way:
The day and month parts of a date are often smaller numbers than the two-digit year part of a date…
And you can square any number by multiplying it by itself…
So, for example, today’s day number is 16, and 16 times 16 is 256…
And today’s month number is 12, and 12 times 12 is 144…
Adding together the squares of the two smaller numbers results in this addition problem:
256 + 144 = 400
Today’s year number, of course, is 2020, but we commonly leave off the first two digits of a year…so the year number is 20.
And 20 times 20 is 400!
So today’s date (12/16/20 or 16.12.20) follows the Pythagorean formula, even though it has nothing to do with triangles, right or otherwise!
Today is special – Pythagorean Theorem Day certainly doesn’t happen every year! – but it HAS happened before and will again:
The last time we experienced Pythagorean Theorem Day was August 15, 2017 (8/15/17 or 15.8.17).
And the next time we will experience Pythagorean Theorem Day will be July 24, 2025 (7/24/25 or 24.7.25).
Also on this date:
National Day in Bahrain
Author Jane Austen’s birthday
Scientist and author Arthur C. Clarke’s birthday
Anniversary of the invention of the transistor
Kazakhstan’s Independence Day
Check out my Pinterest pages on:
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December holidays
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December birthdays
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Historical anniversaries in December
And here are my Pinterest boards for:
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January holidays
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January birthdays
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Historical anniversaries in January