21 US customary cups in US dry barrels

Conversion formula
How to convert 21 US customary cups to US dry barrels?

We know (by definition) that: $1\mathrm{uscup}\approx 0.00204613095238095\mathrm{drybarrel}$

We can set up a proportion to solve for the number of US dry barrels.

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

Conclusion: 21 ⁢ uscup ≈ 0.042968749999999944 ⁢ drybarrel

Conversion in the opposite direction

The inverse of the conversion factor is that 1 US dry barrel is equal to 23.2727272727273 times 21 US customary cups.

It can also be expressed as: 21 US customary cups is equal to $\frac{1}{\mathrm{23.2727272727273}}$ US dry barrels.

Approximation

An approximate numerical result would be: twenty-one US customary cups is about zero point zero four US dry barrels, or alternatively, a US dry barrel is about twenty-three point two six times twenty-one US customary cups.