Degrees in a circle?

Question

Why are there 360 degrees in a circle? Does it have anything to do with the Earth orbiting the sun? Does this come from the egyptians? Thanks

Answer 1

Circles were NOT invented in America. Many ancient cultures studied and calculated the value of pi and they needed to have knowledge of circles to be able to do that, Read some of Euclid's plane geometry!

One such culture was the Babylonians (in modern day Iraq) who worked out pi to be 355/113, (accurate to 6 decimal places).

360 degrees in a circle also came from the Babylonians, about 3,800 years ago. They had a base-60 mathematical system (a sexagesimal system). And so they divided the circle into 60 minutes and the minute into 60 seconds. And they then applied the system of minutes and seconds to hours as well.

It worked well, it spread and the Egyptians and Greeks copied them and that is how we have got what we have today.

The Babylonians had a 360-day year too (with 12 30-day months) and added an extra month of 30 days once every six years to squeeze 6 lots of 5 days in. To keep the seasons and the calendar in phase with one another.

Answer 2

Actually the Babylonians got it from the Sumerians. They did all the neat number stuff. They put 7 days in a week. 24 hours in a day. 60 minutes an hour etc. 360 degrees (90 for a right angle) is also their invention. I think the reason for 360 degrees is that the number is easily factorable by dividing by 2,3,4,5,6, 8, 12, 20 etc without using to many fractions. This also works for their time measures except the week.

Interestingly, most American measurements are traditional british ones modified. The multipliers are the same (16 ounches in a lb) but some of the basic quantities are changed (a US gallon is smaller than a uk one)

The Metric system inroduced a decimal approach under Napolean and is essentially French in origin. They have a system where there are indeed 400 grads or gradians in a circle. This is generally not used elsewhere.

Answer 3

Probably be4cause so many numbers divide into it without creating messy fractions: 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20 Whereas with a 100 degree circle you would only have 2, 4, 5, 10, 20

Answer 4

Basically, the answer is yes, it has to do with the Solar year (which was thought to be 360 days). But I'm not sure if it was the Egyptian or the Persians or someone else who first started using 360 degrees in a circle. In any case, 2π radians in a circle makes a whole lot more sense as a unit of circular (arc) measurement ☺


Doug

Answer 5

The Babalonyians gave us 360 degrees in a circle. Rather than than the decimal system we use today, they used base 60!!! Consequently having 360 degrees in a circle is a purely arbitrary value which is not based on any underlying physical laws or constants. A bit like the metre.

Answer 6

No degrees in a circle, there are 360 degrees in a revolution. And yes, it did come from the Egyptians.

Answer 7

I'm sure that there are extra theories that link 360 to the number of degrees. But the main reason is because the Egyptians (or Babylonians, I can't remember which) used a counting method of base 60. We use a base of 10. Which means we count to 10, then we roll over, it is the same principle applied to a base of 60.

Answer 8

It comes from the Greeks, a Greek philosopher (I forget the name) worked out the orbit of the sun using a series of slaves stationed at certain points across Greece.
After some complicated maths he divided the circle and such.

Answer 9

I guess because circles were invented in America. If they had been invented in the UK, there would probably be 100 or 1000 degrees in a circle. We would not have increments like minutes and seconds either. From our experience with UK measurements I imagine we would have increments of a degree such as Centicrements, and Milliecrements. Having said all that, when it came to measurements involving area of circles, since circles were invented in America, we use this magic number that is something like 3.141517 for those calculations. If circles had been invented in the UK, we would have to use some stupid number like 14.1 Newtons..

Answer 10

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