Answer
$y=4$, see graph.
Work Step by Step
Step 1. Rewrite the equation as $r=\frac{4sin\theta}{cos^2\theta}$ or $r\ cos\theta =4cot\theta$
Step 2. Using $x=r\ cos\theta$ and $cot\theta=\frac{x}{y}$, we have $x=\frac{4x}{y}$ which gives $y=4$
Step 3. We can graph this line function as shown in the figure.
