Answer
The rectangular equation is, $y=4$
Work Step by Step
Using, $r\sin \theta =y$, we will convert the polar equation to the rectangular equation.
Therefore,
$\begin{align}
& r=4\csc \theta \\
& r=\frac{4}{\sin \theta } \\
& r\sin \theta =4 \\
& y=4
\end{align}$
