# Happy Square Root Day!

Today is March 3rd, 2009.  That is, 3-3-09.  But $3^{2}=9$ which makes it a square root day.  So be sure to eat a radish, rutabaga, rengarenga, or other root vegetable!

A Babylonian tablet from 1700 BC with a representation of the square root of 2.

The earliest evidence of square roots is from Babylonianian mathematics during 1800 – 1600 BC.  The above picture is the Babylonian tablet YBC 7289 from the Yale Babylonian Collection.  It was photographed by Bill Casselman of the University of British Columbia Math Department.  You can find his photos here and a discussion of his interpretation of the tablet here.

## 5 thoughts on “Happy Square Root Day!”

1. Do carrots count?

It’s impressive they approximated the square root of two that accurately.

Why did they use base 60?

• I agree, the Babylonian mathematics is impressively sophisticated. If I recall correctly, the reason they preferred base 60 was because 60 is evenly divisible by quite a few different numbers so it makes it easy to work with fractional amounts. This is part of the reason we still use base 60 for time (60 seconds in a minute, etc.) and in angles (360 degrees in a circle, etc.).

2. I have another interesting story that is similar to this one. This dilemma was solved by Imam Ali

When Imam Ali was riding his horse, he saw a man who was gesturing to him to stop. He did what the man wanted and asked him: ” How can I help you?” The man said hi and asked Imam Ali:” Could you find a number which is divisible by 1,2,3,4,5,6,7,8 and 9. Imam Ali smiled and replied: ” multiply the number of days in a week by the number of days in a year ( which is 360 at that time)

360*7= 2520

And this number is divisible by 1,2,3,4,5,6,7,8 and 9

3. When Imam Ali was riding his horse, he saw a man who was gesturing to him to stop. He did what the man wanted and asked him: ” How can I help you?” The man said hi and asked Imam Ali:” Could you find a number which is divisible by 1,2,3,4,5,6,7,8 and 9. Imam Ali smiled and replied: ” multiply the number of days in a week by the number of days in a year ( which is 360 at that time)

360*7= 2520

And this number is divisible by 1,2,3,4,5,6,7,8 and 9