There are many views on the origin of 360 degrees, of which two are dominant.
1. Regarding the ephemeris
In ancient times, people used the Sun, Moon, stars and other natural phenomena to measure time and create calendars. Among them, the position of the Sun is very important for compiling the solar calendar.
The Sumerians observed the Sun, Moon, and five visible planets (Mercury, Venus, Mars, Jupiter, and Saturn), mainly for omens. They are not trying to understand physical movements. However, they noticed the circular orbit of the Sun’s annual path across the sky and knew that it takes about 360 days to complete one cycle of the year. Therefore, they divided the circle into 360 degrees to track the entire journey of the Sun during each day. This probably happened around 2400 BC. This is the origin of the earliest 360-degree system.
The number 360 was probably chosen because it was the number of days in the year of the ancients. Primitive calendars, such as the Persian calendar, used 360 days in a year. Its application to measuring angles in geometry can be traced back to the days of Thales, who popularized geometry among the Greeks and lived in western Turkey among the Egyptians and Babylonians. .
2. Relative to base 60
In the early days, people often used their fingers to count, so the number base was 10, called the decimal system. Hindu-Arabic numerals are the most popular set of symbols to represent numbers. They are considered one of the most important achievements in mathematics which is also a system of counting and calculation based on 10.
But in ancient times, some civilizations used 60 as the base, called the hexadecimal system (Base 60). Base 60 is one of the ancient methods of human counting, originating with the ancient Semites in the 3rd century BC and later spread to Babylon and other places.
The reason why 60 is used instead of other numbers is probably because 60 is a relatively small number and can be divided into 10 real factors of 2, 3, 4, 5, 6, 10, 12, 15 , 20 and 30 this makes base 60 more flexible for different calculations.
In addition, the use of base 60 is also convenient for drawing with a ruler and ruler. In the lunar calendar of the East, there is the concept of hexagonal flower armor, which is a combination of 6 cycles of can and 5 cycles of chi to form a system of 60.
As Greek geometry developed, it gave rise to the concept of angles and degrees. One of the minds who laid the foundation for Greek geometry was the mathematician Euclid (who lived in the 3rd century BC) with a series of books on mathematics and geometry called “Basics”.
The base 60 counting method was then spread to Europe by the Arabs, eventually becoming the mainstream method, which is now widely used in time, angle, geographic coordinates and other fields.
Around 300 to 100 BC, the Babylonians broke down the hour into base 60 fractions: 60 minutes in an hour and 60 seconds in a minute. The base 60 of their number system still exists in our angular and time divisions (1 hour = 60 minutes, 1 minute = 60 seconds, but 1 second = 1000 milliseconds – because milliseconds appear). in modern times and base 10 has become mainstream at this time).
The reason a circle has a circumference of 360 degrees instead of 60 degrees is probably because the ancients found that there are exactly 6 equilateral triangles whose sides are the radius of the circle and the angles of the equilateral triangle are also 60 degrees. , so 6 triangles will form 360 degrees.
One degree is divided into 60 minutes, and one minute into 60 seconds. These units, also known as angular minutes or angular seconds, respectively, are represented by a single or double spread, or by a single or double quotation mark, respectively.
Therefore, using 360 degrees to represent the angle is more convenient than 100, because it can be divided into many different angles and these angles are all integers, making calculations more convenient and reducing the possibility of errors. calculation error.
In summary, the origin of 360 degrees as an angular unit can be traced back to ancient civilizations, it has advantages and meanings in many aspects such as history, culture, technology and mathematics. It has become an integral part of modern science and engineering.
The number 100 is simpler, but it does not meet these requirements well, so 360 degrees becomes a commonly used unit of angle measurement. Although other angular units (such as radians) have their own unique application scenarios, 360 degrees, as a universal unit of angle, has become the most common measurement in the world. scientific and technical fields.
