640 kilometers in centimeters

Conversion formula
How to convert 640 kilometers to centimeters?

We know (by definition) that: $1\mathrm{km}=100000\mathrm{cm}$

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

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

Conclusion: 640 ⁢ km = 64000000 ⁢ cm

Conversion in the opposite direction

The inverse of the conversion factor is that 1 centimeter is equal to 1.5625e-08 times 640 kilometers.

It can also be expressed as: 640 kilometers is equal to $\frac{1}{\mathrm{1.5625e-08}}$ centimeters.

Approximation

An approximate numerical result would be: six hundred and forty kilometers is about sixty-four million centimeters, or alternatively, a centimeter is about zero times six hundred and forty kilometers.