21 kilometers in feet

Conversion formula
How to convert 21 kilometers to feet?

We know (by definition) that: $1\mathrm{km}\approx 3280.8399\mathrm{ft}$

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

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

Conclusion: 21 ⁢ km ≈ 68897.6379 ⁢ ft

Conversion in the opposite direction

The inverse of the conversion factor is that 1 foot is equal to 1.45142857142857e-05 times 21 kilometers.

It can also be expressed as: 21 kilometers is equal to $\frac{1}{\mathrm{1.45142857142857e-05}}$ feet.

Approximation

An approximate numerical result would be: twenty-one kilometers is about sixty-eight thousand, eight hundred and ninety-seven point six three feet, or alternatively, a foot is about zero times twenty-one kilometers.