21 centimeters in decimeters

Result

The conversion result is: 21 centimeters is equivalent to 2.1 decimeters.^[1]

Conversion formula
How to convert 21 centimeters to decimeters?

We know (by definition) that: 1 cm = 0.1 dm.

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

1 cm / 21 cm = 0.1 dm / x dm

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

x dm = (21 cm / 1 cm) * 0.1 dm → x dm = 2.1 dm

Conclusion:

21 cm = 2.1 dm

Conversion in the opposite direction

The inverse of the conversion factor is that 1 decimeter is equal to 0.476190476190476 times 21 centimeters.

It can also be expressed as: 21 centimeters is equal to 1 / 0.476190476190476 decimeters.

Approximation

An approximate numerical result would be: twenty-one centimeters is about zero decimeters, or alternatively, a decimeter is about zero point four eight times twenty-one centimeters.