How can you convert centimeters to millimeters?
Quick Answer: Multiply by 10.
To do any conversion, you find the relationship between the two units.
In this case,
This gives you two conversion factors:
and if you look at the equation, you'll see that
Convert 3.1 cm into millimetres.
You multiply by a conversion factor:
Choose the one that gives you the correct units for the answer.
Note that the "cm" cancels out and leaves you with the answer in “mm”. If you had chosen the other conversion factor, you would have gotten
The strange units for the answer tell you that you have made a mistake.
If you can’t remember that
Then you can convert “cm” to “m” and “m” to “mm”.
It's an extra step, but it always works.