check the picture below.
now, there are 1000 liters in 1m³, so in 1875 m³, there are 1875*1000 liters, or 1,875,000 liters, now, how many gallons is that?
[tex]\bf \begin{array}{ccll}
gallons&liters\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
1&3.789\\
g&1875000
\end{array}\implies \cfrac{1}{g}=\cfrac{3.789}{1875000}\implies \cfrac{1875000}{3.789}=g[/tex]