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360 degrees

  1. Jun 4, 2005 #1
    Why was the number '360' chosen to be the number of degrees in a complete revolution? How far back does the number go?
  2. jcsd
  3. Jun 4, 2005 #2
    I'd think it was something to do with the number of days in the year that they believed was correct at the time. Also it is easy to divide it up I guess...

    I'm not too good on the history of science...
  4. Jun 4, 2005 #3
    There are easier numbers to divide. I just dont see any logical sense as to why 360 was chosen.
  5. Jun 4, 2005 #4
    I still think its something to do with the number of days in the year...
  6. Jun 4, 2005 #5
    A site I checked out claimed this exerpt was from a book called 'The History of Pi' by Petr Beckman.

  7. Jun 4, 2005 #6
    cool :D - well at least I learned something new staying up this late revising....
  8. Jun 4, 2005 #7
    So the 360 is somewhat arbitrary, and could be replaced by any figure, or does it truly represent something about a circle (or an angle)?
  9. Jun 4, 2005 #8
    It seems to be arbitrary. The Babylonians chose 60 as their numeric base rather than 10. 60 can be divided without remainder by 1,2,3,4,5 and 6. 60x6=360. Seems that avoiding decimals is the main reason it was put into use.

  10. Jun 4, 2005 #9
    Interesting stuff, thanks alot.
  11. Jun 4, 2005 #10
    Whoa. The babylonians used...base 60? That means they'd need 60 individual symbols for the numbers 0 through 59, right? o_O
  12. Jun 4, 2005 #11
    Last edited: Jun 4, 2005
  13. Jun 4, 2005 #12
    That sounds okay, but then there are numbers that have a more factors than 60. why was it just sixty? For example, setting it at 120 would give them 1,2,3,4,5,6,8,10.
  14. Jun 4, 2005 #13
    This comes from the site posted above. They go over some possible explanations, but none are conclusive. There may not be an answer.

    Looking at their system of numerals it looks like using a base of 120 would give them one more numeral that would not result in decimals and would create much more difficulty in expressing those numbers. The example in the text states that 424000 would be written in Sumerian by using the numbers 1,57,46,40. They would have to calculate 1 x 60^3 + 57 x 60^2 + 46 x 60 + 40 = 424000. With a base of 120 they would need over twice as many numerals and would need to calculate by hand much larger numbers. That is my guess.
  15. Jun 5, 2005 #14
    But then one could argue that a number smaller than 60, perhaps 30, would make that calculation even easier. I wonder what their real reason was.
  16. Jun 5, 2005 #15
    Very true. Your guess is as good as mine, probably better. My understanding of math sucks.
  17. Jun 5, 2005 #16
    Thanks for the help man.
  18. Jun 5, 2005 #17


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    This is just a total guess, but I imagine the reason for using such a large base might have been because they (or those from whom they inherited the system) started out without only single symbol representations for all the numbers considered important to them. It's possible that when they started out that no one could imagine a use for a number greater than 60. Perhaps only later someone thought up the "juxiposition" notation for numbers greater than 60 and by then they needed to keep the same sixty digits for "backward compatibilty".
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