Answer
$$r = 2\csc \theta $$
Work Step by Step
$$\eqalign{
& y = 2 \cr
& {\text{Where }}r\sin \theta = y,{\text{ then}} \cr
& r\sin \theta = 2 \cr
& r = \frac{2}{{\sin \theta }} \cr
& {\text{Simplify}} \cr
& r = 2\csc \theta \cr} $$
