Answer
$\frac{5}{3}=\frac{7}{5}$
False
Work Step by Step
x is to y is the same as $\frac{x}{y}$
To determine if a proportion is true, we have to find if the cross products are equal.
The cross products of $\frac{a}{b}=\frac{c}{d}$ are $a \cdot d$ and $b \cdot c$.
Five is to three as seven is to five is the same as $\frac{5}{3}=\frac{7}{5}$
This proportion is false because $5*5=25, 7*3=21, 25 \neq 21$
