640 centimeters in decimeters

Conversion formula
How to convert 640 centimeters to decimeters?

We know (by definition) that: $1\mathrm{cm}=0.1\mathrm{dm}$

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

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

Conclusion: 640 ⁢ cm = 64.0 ⁢ dm

Conversion in the opposite direction

The inverse of the conversion factor is that 1 decimeter is equal to 0.015625 times 640 centimeters.

It can also be expressed as: 640 centimeters is equal to $\frac{1}{\mathrm{0.015625}}$ decimeters.

Approximation

An approximate numerical result would be: six hundred and forty centimeters is about zero decimeters, or alternatively, a decimeter is about zero point zero two times six hundred and forty centimeters.