Question

Write a proportion you could use to convert 2.5 gallons to quarts.

Answer 1

We know there are 4 quarts in a gallon, so how many quarts in 2.5 gallons anyway?

$\bf \begin{array}{ccll} quarts&gallons\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 4&1\\ x&2.5 \end{array}\implies \cfrac{4}{x}=\cfrac{1}{2.5}\implies \cfrac{4\cdot 2.5}{1}=x$