Question #335b3

1 Answer
Feb 26, 2016

The degrees in a circle are an approximation of the days in a year.

Explanation:

Ancient Sumerians and Babylonians did not use decimal (base 10) counting systems. Sumerians used a base 12 counting system, and a year can be conveniently divided into 12 segments. Each segment corresponded to the amount of time for the moon to complete one cycle of phases, or approximately 30 days.

#12 " months" xx 30 " days" = 360 " days"#

Of course, the Sumerians recognized that there were 365 days in a year, but 365 is not cleanly divisible by 12. However, one year is a cycle, and cycles can be modeled using circles. For convenience, the circle was approximated so that each degree corresponds to approximately one day, but the total arc of a circle is divisible by 12.

Later, the Babylonians, who used a base 60 counting system, adopted the Sumerian's system, but further divided each degree into 60 minutes, and each minute into 60 seconds.

#1^@ = 60 ' = 360''#