Find the cartesian equation of $\displaystyle r^2 = 9\csc(20)$?

choices:

A. xy = 9

B. 3xy = 9

C. 2xy = 9

D. 4xy = 9

This is what ive done

$\displaystyle (r^2= \frac{9}{\sin(20)}) \frac{1}{r}$

$\displaystyle \sqrt{x^2 + y^2} = \frac{9}{y}$

$\displaystyle x^2 + y^2 = \frac{81}{y^2}$

$\displaystyle y^2(x^2 + y^2) = 81$