Answer
$\frac{\pi}{2}\leq \Theta \leq 2\pi $ ,$0\leq r \leq 9$
Work Step by Step
describing the given region in polar coordinates of the graph below
as
$x^2+y^2=9^2$
=> $r=9$
=> $\frac{\pi}{2}\leq \Theta \leq 2\pi $ ,$0\leq r \leq 9$