21 feet in centimeters

Conversion formula
How to convert 21 feet to centimeters?

We know (by definition) that: $1\mathrm{ft}=30.48\mathrm{cm}$

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

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

Conclusion: 21 ⁢ ft = 640.08 ⁢ cm

Conversion in the opposite direction

The inverse of the conversion factor is that 1 centimeter is equal to 0.00156230471191101 times 21 feet.

It can also be expressed as: 21 feet is equal to $\frac{1}{\mathrm{0.00156230471191101}}$ centimeters.

Approximation

An approximate numerical result would be: twenty-one feet is about zero centimeters, or alternatively, a centimeter is about zero times twenty-one feet.