40 miles in kilometers

Conversion formula
How to convert 40 miles to kilometers?

We know (by definition) that: $1\mathrm{mile}=1.609344\mathrm{km}$

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

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

Conclusion: 40 ⁢ mile = 64.37376 ⁢ km

Conversion in the opposite direction

The inverse of the conversion factor is that 1 kilometer is equal to 0.0155342798059333 times 40 miles.

It can also be expressed as: 40 miles is equal to $\frac{1}{\mathrm{0.0155342798059333}}$ kilometers.

Approximation

An approximate numerical result would be: forty miles is about sixty-four point three seven kilometers, or alternatively, a kilometer is about zero point zero two times forty miles.