Square Root Day!


carrotsI was driving into work today, and when I turned on my radio I heard that it was Square Root Day.  Except I missed the part where they were explaining what it is, and all I heard was that it won’t happen again for a while, and I thought to myself, “Huh?  But isn’t EVERY day a square root day, since 3 is the square root of 9, and tomorrow, the 4th, will be the square root of 16?”  And I was completely confused.

Then just a few minutes ago, my friend Cheryl popped into my office and said, “HAPPY SQUARE ROOT DAY!”  And she was able to explain this holiday:  it’s because it’s 3-3-09, and 3 is the square root of 09.  Then the light shown shone down and angles sang* and it all made sense.  And the radio was right about the rarity — the next one isn’t until 4-4-16.

And as soon as Cheryl left, my student Adele popped into my office and apologized for overhearing our conversion (nice of her, but unnecessary — my office is right off of the Math Center and I listen to student conversations all the time).  Anyway, Adele passed along that she also had heard about Square Root Day!  It turns out that it’s all over the internet.  Apparently you’re supposed to eat root vegetables cut into squares.  This might explain why it’s not as celebrated a holiday as Pi(e) Day.  So without further ado,

Happy Square Root Day!

Just so I’m not behind on another holiday, Thursday and Saturday are Odd Days, since 3-5-9 and 3-7-9 are odd numbers in increasing order.  Celebrate away!

*I started to write “angels” and misspelled it, but decided that angles singing was more appropriate.

21 Responses to “Square Root Day!”

  1. David P Says:

    I am just curious why they call it by this name. “Factors Day” or even “Perfect Squares Day” seem to make more sense. Reserve “Square Root Day” for 1-6-04 or something like that.

  2. Michael Swart Says:

    Nit pickers R us:
    It’s “shone” down instead of “shown” down. I get an image in my head of a lamp being shown goose feathers 🙂


    The year is not really a square is it? it’s 2009 not 9.

    It’s like being superstitious about the number 113 or 2013.

    Now, February 14, 2025 would be a special day. It’s the 45th day of the 45^2 year.

  3. Ξ Says:

    David, I guess it could go either way. If you’re starting with (the last two digits of) the year, and then try to find a date that works, you’re looking for square roots. If you start with the Monday and Day, it’s more like a Square day.

    Michael, I made the correction; you should see the errors that I manage to catch! You’re right about the year, although the truncation does allow fun dates like 9-9-9 at the beginning of each century!

  4. David P Says:

    Oh! I get it now. You take the “dash” from between the month and date and it is 3 and -3 as the roots of 09 (although there is another dash before the year foiling the extended understanding).

  5. PLUSC Says:

    The real question is… is there any food in the Math Center to celebrate Square Root day?????

  6. Joe Says:

    Wouldn’t 3/2/09 be more general? (Where the 2 is the power.) Why must the root necessarily be square? 2/3/08 was a cube root day, but I never heard anything about that.

  7. Square Root Day? How about an activity…? « JD2718 Says:

    […] quite get it. Three squared is 9. But then wouldn’t that be Square Day? (Apparently Ξ mentioned it, too. And probably a gazillion more bloggers). Hmm. Actually, an alum IM’ed me […]

  8. jd2718 Says:

    I just had the next to last bowl of my latest winter soup. The carrots are circles (well, little cylinders). But the parsnips? Cut in squares.

    And I didn’t even think – square roots.


  9. jd2718 Says:

    Last year I cut some of the parsnips into squares, too. Even though there was no square root day. Look at the photo top right

  10. Ξ Says:

    I noticed some triangles in there too, jonathan — there’s a veritable garden of geometry. And actually, if you cut them into cubes then you have cube roots, which would have been great on Feb 8 last year (as you point out, Joe).

    PlusC, the Math Center was pretty much devoid of food today. I think we’re all saving up for the Pie Contest next week.

    David P — I never thought about the -3. I think you just took the holiday to the next level! It does raise issues about cube root day, though — parts of that must be imaginary.

  11. TwoPi Says:

    Put me “squarely” in the ‘bah, humbug’ camp on this one.

    Next year, I’m celebrating Rectangle Day on February 5th.

    Did folk get excited about Pythagorean Day on March 4th, 2005? Will they on May 12, 2013?

  12. jd2718 Says:

    I made a puzzle out of “rectangle day” in my class yesterday, though I didn’t call it that. The kids were really into it


  13. TwoPi Says:

    I like your puzzle. Mainly because, as you say, the kids were really into it! I can’t argue with success, even if I don’t get the appeal. Yay for improvising in the classroom, especially when it works!

    (I jokingly wondered in email to my brother yesterday why he and I hadn’t ever heard of square root day in school, realizing that only one of them had occurred during my school years — in early September — and for my brother, unless he had gone to summer school he’d have missed out entirely. Likewise for my father….)

  14. Square Root Day? How about Pythagorean Day? « JD2718 Says:

    […] I went back to the well. Over at 360, TwoPi had suggested Pythagorean Day. I ran with […]

  15. veggiedude Says:

    B O R I N G !

    UNIX day (celebrating 1234567890 on Feb 13) was far more impressive.


  16. Batman Says:

    I also recall celebrating 1234567890 in the early afternoon of July 8, 1990.

  17. Lambchop Says:

    Hey! TwoPi! May 2nd next year would also work, right?!

  18. TwoPi Says:

    Lambchop: Indeed! As will January 10, and October 1.

    Celebrating Rectangle Day will be more difficult in 2037, though.

  19. Lambchop Says:

    As well as this year, I betcha!

  20. TwoPi Says:

    We’ve missed January 9th, but there’s still September 1st.

    And depending on your sensibilities (or nationality), March 3rd arguably was also a Rectangle Day.

    2037 will be the next year without a Rectangle Day at all, but of course it is not the first year of this millennium without one.

  21. TwoPi Says:

    Oh wait, daft of me. YES, actually 2037 IS the first year of the millennium without a Rectangle Day, since 2000 was in the last millennium, not this one.

    (Got muddled in the morning counting down to zero. My bad.)

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: