Answer
Symmetrical about the vertical line $θ = \frac{\pi}{2}$
Work Step by Step
The rules for symmetry:
1. About the Polar Axis if the graph is the same when replacing θ with -θ
2. About the pole if the graph is the same when replacing r with -r or θ by $θ + \pi$
3. About the vertical line $θ = \frac{\pi}{2}$ if the graph is the same when replacing θ by $\pi - θ$
Given $r = 2 - \sin θ$
1. $r = 2 - \sin (-θ) = 2 + \sin (θ)$
Not the same, so not about the polar axis
2. $-r = 2 - \sin (θ) = \sin θ - 2$
Not the same, so not about the pole
3. $r = 2 - \sin (\pi - θ) = 2 - \sin (θ)$
Yes!
Symmetrical about the vertical line $θ = \frac{\pi}{2}$
