whya are their 360 degrees in circle

A line of ancient people(Sumerians Alkadians and Babylonians)who lived in Mesoptamia invented writing.About 3000 BC the Sumerians invented writing. They also had a cakendar dating from 2400 BC, divided the year in to 12 months of 30 days tha is 360 days .The sumerians watched the sun , moon and the five visible planets (Mercury, Venus, Jupitor, and Saturan)primarily for omens. They did not try to understand the motion physically . They never notice circular track of sun`s annual path across the sky and knew that it took about 360 days to complete one years circuit .Consequently they divided the circular path in to 360 degree to track each day`s passage of the sun`s whoile journey .This probably happened about in 2400 B»C