Answer
cross products
Work Step by Step
When fractions are equivalent, the cross products are equivalent. The term cross product is derived from the X shape of the numbers being multiplied.
$\frac{a}{b}=\frac{x}{y}$
$\frac{a}{b}\nearrow\!\!\!\!\!\!\searrow\frac{x}{y}$ $\Rightarrow ay=bx$