Today, 8-15-17, by many math aficionados’ accounts, is a cause célèbre since it satisfies the Pythagorean theorem.  In other words, 8, 15, and 17 could be the lengths of the sides of a right triangle because 8 squared (64) plus 15 squared (225) is equal to the square of 17 (289).

The last time we had a date that was a unique Pythagorean triple was May 12th, 2013 (or, 5-12-13).  One might argue that December 5th, 2013 could have also fit the bill, and since these magical dates come along so infrequently, I am sure we celebrated twice that year.  Alas, we can not do that this year because we do not have a 15th month.

When I shared this with my classes today, most of them were somewhat interested.  In fact, in my first period AP Calculus class one of my students asked, “Did you do that ACT warm up question because of today’s date?”  Why yes, yes I did.

Google seems to laud even the most obscure dates and so when I clicked in to see what they chose to highlight for a Pythagorean triple date, I was aghast to find cosine(pi/2), i.e. nothing.

Enjoy this day while you can… the next Pythagorean triple will be eight years from now in 2025.  July 24th, 2025.  7-24-25.  There is a likelihood that my current 8th grade students will be finished or nearly finished with college at that time.  A multiple of 3-4-5 occurs on December 16th, 2020 (12-16-20), but that’s kinda like tying for second place.