Square Root Day

Square roots are found all other the place in math classes.  Aside from finding the square root of a number, one of the most familiar uses is in the quadratic formula for finding roots of quadratic equations.  One of my coworkers is finishing off a math class and she's been using this formula a lot.

Did you know there is an unofficial holiday referred to as Square Root Day?  Its only been around since 1981, when Ron Gordon held the first square root day on September 9, 1981. Ron Gordon was working as a high school drivers ed teacher at the time.


It was noticed that September 9, 1981 when expressed as 09/09/81 made the perfect square root because 9 x 9 = 81 and 9 is the square root of 81. If you look at all the days in a century, you'll discover that only 9 days meet this criteria. For the 21st century, these are the square root days.

• February 2, 2004 (02/02/04): 2 X 2 or 2² = 4
• March 3, 2009 (03/03/09): 3 X 3 or 3² = 9
• April 4, 2016 (04/04/16): 4 X 4 or 4² = 16
• May 5, 2025 (05/05/25): 5 X 5 or 5² = 25
• June 6, 2036 (06/06/36): 6 X 6 or 6² = 36
• July 7, 2049 (07/07/49): 7 X 7 or 7² = 49
• August 8, 2064 (08/08/64): 8 X 8 or 8² = 64
• September 9, 2081 (09/09/81): 9 X 9 or 9² = 81

The last one occurred on April 4, 2016 and the next one won't be for another 6 years on May 5, 2025.  now for some fun facts about square roots.

1. The first square root sign first appeared in print back in 1525 in the book Cross which also contained the modern + and - for addition and subtraction.

2.  Yale University has a Babylonian Tablet containing the value of the square root of 2 to nine decimal places.  The table is about 4000 years old.

3. The Rhind Mathematical Papyrus, dating back to 1650 BC, shows that Ancient Egyptians had the ability to calculate square roots, along finding slopes.

4. There are clocks out there that show the time in square roots such as noon is the square root of 144.

5.  Even Ancient India had a way of finding square roots and they used square roots as far back as 800 BC.  

I stumbled across this holiday and when 2025 comes around, I'll be ready to celebrate.  Let me know what you think, I'd love to hear.  Have a great day.