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  • (Score: 1) by anubi on Sunday March 16 2014, @10:53AM

    by anubi (2828) on Sunday March 16 2014, @10:53AM (#17147) Journal

    With computerization being what it is, I am surprised that the circle isn't commonly divided up into 256 parts, each part having 256 sub-parts so that the whole thing fits nicely with two's complement integer math.

    I get the idea it would make driving stepper motors a lot more straightforward. I could understand the 360 thing given we have 365 days in a year, which means things will advance almost 1 degree per day... but 365 is a nasty number for division purposes... only good for 5 and 73... 360 is evenly divisible by 2, 3, 4, 5, 6, 8, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, and 180, which makes division into equal parts handy.

    400? I wonder what the reasoning behind that is?

    --
    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
  • (Score: 5, Insightful) by Foobar Bazbot on Sunday March 16 2014, @02:50PM

    by Foobar Bazbot (37) on Sunday March 16 2014, @02:50PM (#17187) Journal

    The choice of 360 degrees is, AIUI, as much from being a round number in the old sumerian/babylonian base-60 system (which is also why degrees are traditionally subdivided by 60 to form minutes and seconds), as from the convenient divisors bit. As for grads, it comes from powers-of-ten-are-awesome post-revolution France, and was created by dividing a right angle into 100ths -- while it was less successful than other metric units that made it into SI, it was at least more successful than the attempted metrification of calendar and clock.

    Another commenter replied to the effect that grads have been obsoleted entirely in favor of "mils"; as the NATO mil is in fact derived from the grad, I'm not sure whether this is actually true. Milliradians are a convenient unit for small-angle trig, because the combination of radians and powers of ten. So given an object of 1 m diameter, which visually subtends an angle of 1 milliradian, is known to be at a range of 1 km. There are of course 2000π, or approximately 6283 milliradians in a circle, which is inconvenient. But subdividing grads into 16 divisions yields a total of 6400 divisions, which is close enough to be used as a milliradian (<2% error), while also being a convenient division of the circle; this approximation to the milliradian is the definition of the "mil" used by NATO.

    (I do know that grads are one of the three trigonometric units available on current-production HP calculators, so somebody must still be using them...)

    • (Score: 1) by anubi on Tuesday March 18 2014, @06:05PM

      by anubi (2828) on Tuesday March 18 2014, @06:05PM (#18188) Journal

      Thanks... I was wondering why someone would coin yet another standard that was so close to a degree.

      Interesting about the Sumerians and the base-60 counting...Looks like I have yet another curiousity to satisfy... as to why the Sumerians were onto that particular base for counting? Seems awkward to me, but then when I finally understand why, I am often marveled at what I discover.

      --
      "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
    • (Score: 1) by PiMuNu on Wednesday March 19 2014, @07:19AM

      by PiMuNu (3823) on Wednesday March 19 2014, @07:19AM (#18447)

      Incidentally, I found out recently that the Sumerians probably used base 12 because they counted phalanges (three phalanges on 4 fingers on each hand), as they still do in some parts of China. Just random fact...

      • (Score: 2) by Fluffeh on Saturday March 22 2014, @08:13AM

        by Fluffeh (954) Subscriber Badge on Saturday March 22 2014, @08:13AM (#19641) Journal

        Actually, they used base 60.

        A number was shown using both hands - one hand showing a value between one and twelve, the other hand showing how many twelves had already been added.

        This is also why there are 24 hours in the day, why each hour is made of 60 minutes and each minute is made of 60 seconds.

    • (Score: 1) by bigjimslade on Sunday March 23 2014, @03:45PM

      by bigjimslade (212) on Sunday March 23 2014, @03:45PM (#19942)

      mils ? really??
      obviously created by theoretical math geeks.

      everyone that has used a piece of machinery understands what a real 'mil' is....

      --
      Remember, Tuesday is Soylent Green Day
  • (Score: 1) by KiloByte on Thursday March 20 2014, @03:49PM

    by KiloByte (375) on Thursday March 20 2014, @03:49PM (#18927)

    This was already done: before degrees, nautical directions were given in rhumbs, with 32 rhumbs making a full circle.

    --
    Ceterum censeo systemd esse delendam.