How to convert 685 feet to kilometers?
We know (by definition) that:
We can set up a proportion to solve for the number of kilometers.
Now, we cross multiply to solve for our unknown :
Conversion in the opposite direction
The inverse of the conversion factor is that 1 kilometer is equal to 4.78954729198996 times 685 feet.
It can also be expressed as: 685 feet is equal to kilometers.
An approximate numerical result would be: six hundred and eighty-five feet is about zero point two one kilometers, or alternatively, a kilometer is about four point seven nine times six hundred and eighty-five feet.
 The precision is 15 significant digits (fourteen digits to the right of the decimal point).Results may contain small errors due to the use of floating point arithmetic.