The Babylonians developed their sexagesimal degree system in about 300 BC. (Their sexagesimal number system is much older.) It was used for astronomical tables at that time. The circle was first divided into sixths, and these were divided by sixty into degrees, thus, our 130 degrees would be (2 10), or 2 sixths plus 10 sixtieths of a sixth.
The sixth is approximately equal to our present radian, which might have been why it was chosen; it is also easy to divide a circle into sixths by marking off radius-length chords. It is easier to determine _that_ something was done than _why_ it was done -- even today. As the saying goes, "There are good reasons and then there are real reasons." For much more on Babylonian mathematics and astronomy see the writings of Otto Neugebauer. Gordon At 11:25 AM 7/8/98 -0700, Andrew B. Johnson wrote: >Why did cartographers and others settle on a compass >divided into 360 degrees? Why not simply 60, to match >the further divisions into 60 minutes and 60 seconds? >Or, if we want to recognise the four "directions" of >the compass, why not into 240 degrees? > >Thanks for your help with this simple question. > >- andrew johnson > berkeley california >
