31 millimeters in kilometers

Conversion formula
How to convert 31 millimeters to kilometers?

We know (by definition) that: $1\mathrm{mm}=1e-06\mathrm{km}$

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

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

Conclusion: 31 ⁢ mm = 3.1e-05 ⁢ km

Conversion in the opposite direction

The inverse of the conversion factor is that 1 kilometer is equal to 32258.064516129 times 31 millimeters.

It can also be expressed as: 31 millimeters is equal to $\frac{1}{\mathrm{32258.064516129}}$ kilometers.

Approximation

An approximate numerical result would be: thirty-one millimeters is about zero kilometers, or alternatively, a kilometer is about thirty-two thousand, two hundred and fifty-eight point zero six times thirty-one millimeters.