Base 60

 Speculative phase: I think base 60 was used due to time: 60 seconds in a minute, 60 minutes in an hour.

- 60 is also divisible by more numbers than 10? 

- There are 12 zodiacs in the Chinese calendar. I am not sure whether that is related to base 60 or not

- I have also seen angle expressed in the form of something like 20°48'. So to convert it to degrees or the modern way of it, we take 48 divided by 60 = 0.8 and that is the decimal places. So it becomes 20.8°

Research phase:

- 60 is a the smallest number that is divisible by all numbers from 1 to 6. I guess this is a very convenient number to use especially when we are talking about time.

- In fact, the Chinese also uses a sexagenary (60 years) cycle to name their years. There are 10 heavenly stems and 12 earthly branches. Of course the names are all in Chinese but for simplicity sake you can think of the 10 heavenly stems as A, B, C, D, E, F, G, H, I, J (I actually learnt them in Hong Kong when I was still in elementary school but it was so long ago I totally forgot about them) and the 12 earthly branches as 1,2,3,4,5,6,7,8,9,10,11 and 12. The 12 earthly branches are also the 12 times of the day in the Chinese time, each earthly branch represents 2 hours, 12 of them make up the 24 hours in one day The way the Chinese name the years looks like this: A1,B2,C3,D4,E5,F6,G7,H8,I9,J10,A11,B12,C1,D2.... and with this pattern we are back to A1 after 60 years. Even up until today, there are still lots of Chinese using this system. Chinese also like to name significant events after the name of the year. A prime example is the the Xin hai Revolution in 1911 that overthrew the Qing dynasty (the last imperial dynasty of China) and established the Republic of China. Here Xin is one of the heavenly stems and Hai is one of the earthly branches.