Approximately ##12.4##
##1## mile is exactly ##1.609344## kilometers.
So ##20## kilometers is ##20/1.609344 ~~ 12.4## miles.
##color(white)()##Bonus
Approximate mile ##harr## kilometer conversions can be made using the Fibonacci sequence:
##1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144,…##
Each term of the Fibonacci sequence is the sum of the previous two terms.
The ratio between pairs of successive terms tends to the “golden ratio” ##~~ 1.618##, which is quite close to ##1.609344##.
So we find that ##5## miles is about ##8## kilometers, ##21## kilometers is about ##13## miles, etc.
In the case of ##20## kilometers, we can approximate by:
##20 = 21 – 2/2 rarr 13 – 1/2 = 12.5##
or:
##20 = 21 – 5/5 rarr 13 – 3/5 = 12.4##
