21 decimeters in kilometers

Conversion formula
How to convert 21 decimeters to kilometers?

We know (by definition) that: $1\mathrm{dm}=0.0001\mathrm{km}$

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

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

Conclusion: 21 ⁢ dm = 0.0021000000000000003 ⁢ km

Conversion in the opposite direction

The inverse of the conversion factor is that 1 kilometer is equal to 476.190476190476 times 21 decimeters.

It can also be expressed as: 21 decimeters is equal to $\frac{1}{\mathrm{476.190476190476}}$ kilometers.

Approximation

An approximate numerical result would be: twenty-one decimeters is about zero kilometers, or alternatively, a kilometer is about four hundred and seventy-six point one eight times twenty-one decimeters.