### Why 360?

Sunday, October 4, 2009
Have you ever wondered why does a circle have 360 degrees? Well I haven't really thought about it, I just went with it until the question came up in math class and then I found out.

It started out with the Babylonians and they had a base 60 number system. We use this base 60 number system in our time like 60 minutes in an hour and 60 seconds in a minute. But we have a base 10 number system. The base 60 system is called the Sexagesimal system. The Babylonians took their base and multiplied it by 6. And they came up with 360.

360 was very close to how many days are in a year. There are actually 365.25 days in a year. The Babylonians had a calendar that consisted of 360 days a year. The Babylonians did research and watched the sky and the sun and they realized that it took at least 360 days to go though the whole process. They were very close but they thought the Sun went around the earth in 360 days. But the earth goes around the sun in 365 days.

There are 360 different sunset points of entry on the horizon during a calendar year (to the naked eye). 90 points / days between Winter Solstice to Equinox, Equinox to Summer Solstice, Summer Solstice to Equinox and then Equinox to Winter Solstice. And that is basically all 4 seasons.

The base 60 system is also very common and is a common number too. Many numbers go into 60. Like the numbers 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 24, 30, and 60.

The numbers from the base 60 number system looks like this.

(sorry if the picture is blurry just go to this site if you cannot see)

linda 9-05 said...

Great job, Zerlina! I like your use of colour and your pictures are wonderful. Although there is always room for improvement! Some changes you can make are to fix calender to calendar, capitilizing Babylonians, since they were a civilization, capitilizing the Sun, and also adding the word "number" after common in your second last paragraph because it's a fragment sentence. There are a few grammar errors but that's not so much of a big deal. You spent a great portion of your post explaining the calendar so you kind of strayed away from the main point, which was to explain why we use 360 degrees. Keep up the great work! :D

Lissa 9-05 said...

Awesome work Zerlina! Your pictures are awesome and they show very clearly if you were wondering if they were blurry. By the way, my favourite picture is the 60 number system. It looks cool (: But, it also looks very confusing.. Anyways, good job!