21 dry gallons in US customary cups

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

We know (by definition) that: $1\mathrm{drygallon}\approx 18.618354978355\mathrm{uscup}$

We can set up a proportion to solve for the number of US customary cups.

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

Conclusion: 21 ⁢ drygallon ≈ 390.985454545455 ⁢ uscup

Conversion in the opposite direction

The inverse of the conversion factor is that 1 US customary cup is equal to 0.00255763990290269 times 21 dry gallons.

It can also be expressed as: 21 dry gallons is equal to $\frac{1}{\mathrm{0.00255763990290269}}$ US customary cups.

Approximation

An approximate numerical result would be: twenty-one dry gallons is about three hundred and ninety point nine nine US customary cups, or alternatively, a US customary cup is about zero times twenty-one dry gallons.