公里是公制系统中长度的单位，等同于1000米。
英里也是长度单位，等于1760码。
例子：
Input: 5.5
Output: 3.418
Input: 6.5
Output: 4.039
公式：
1 kilometer equals 0.62137 miles.
Miles = kilometer * 0.62137
Kilometer = Miles / 0.62137
# Python3 program to convert
# kilometers to miles
# driver code
kilometers = 5.5
# conversion factor
conv = 0.621371
# calculate miles
miles = kilometers * conv
print('%0.3f kilometers is equal to %0.3f miles' %(kilometers,miles))
kilometers = 6.5
# calculate miles
miles = kilometers * conv
print('%0.3f kilometers is equal to %0.3f miles' %(kilometers,miles))
输出：
5.500 kilometers is equal to 3.418 miles
6.500 kilometers is equal to 4.039 miles