21 kilometers in miles

Conversion formula
How to convert 21 kilometers to miles?

We know (by definition) that: $1\mathrm{km}\approx 0.62137119\mathrm{mile}$

We can set up a proportion to solve for the number of miles.

Now, we cross multiply to solve for our unknown $x$:

Conclusion: 21 ⁢ km ≈ 13.04879499 ⁢ mile

Conversion in the opposite direction

The inverse of the conversion factor is that 1 mile is equal to 0.0766354285714286 times 21 kilometers.

It can also be expressed as: 21 kilometers is equal to $\frac{1}{\mathrm{0.0766354285714286}}$ miles.

Approximation

An approximate numerical result would be: twenty-one kilometers is about thirteen point zero five miles, or alternatively, a mile is about zero point zero eight times twenty-one kilometers.