Why a full circle is 360 degrees

Day 302 / 365

Everyone knows that a full circle is made up of 4 right angles, i.e, 4 times 90 which is 360 degrees. But that number is a man-made thing, just like we decided that there will be 7 days in a week and 24 hours in a day. Why did we choose a number like 360 and not something like 100 or 1000 which sounds more easier to work with? There are lots of theories behind this

The Mathematical Reason

If the circle was 100 degrees, it would actually make calculations tougher. It’s fine if you wanna divide it into 2 or 4 parts, but what about 3? that would give you 33.3333…. for each part, which is not so great.

100 is perfectly divisible by only 9 numbers. Compared to that, 360 has 24 divisors. Thus it is much easier to divide 360 into smaller parts.

Number of days in a year

360 is also quite close to 365, which is the number of days we have in a year. Our ancestors knew that the sun took 365 days to come back to the exact same position. They rounded it down to 360 for simplicity. The Persians had a leap month every 6 years to adjust for the extra 5 days.

This post is part of my 365 Day Project for 2019. Read about it here

Yesterday’s blog — How Chinese Keyboards Work