21 US gallons in US dry barrels

Conversion formula
How to convert 21 US gallons to US dry barrels?

We know (by definition) that: $1\mathrm{usgallon}\approx 0.0327380952380952\mathrm{drybarrel}$

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 ⁢ usgallon ≈ 0.6874999999999991 ⁢ drybarrel

Conversion in the opposite direction

The inverse of the conversion factor is that 1 US dry barrel is equal to 1.45454545454545 times 21 US gallons.

It can also be expressed as: 21 US gallons is equal to $\frac{1}{\mathrm{1.45454545454545}}$ US dry barrels.

Approximation

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