Answer
$y=4.5$
Work Step by Step
To find $y$ when $x=3$, set up a proportion using two forms of $\frac{y}{x}$
$\frac{\frac{3}{4}}{\frac{1}{2}}=\frac{y}{3}$
Now write the cross products
$\frac{3}{4}(3)=(\frac{1}{2})y$
Simplify
$2.25=(\frac{1}{2})y$
Multiply each side by 2
$2(2.25)=(\frac{1}{2})y(2)$
Simplify
$4.5=y$