Answer
$(-\frac{3\sqrt 3}{2}, \frac{3}{2})$
Work Step by Step
Step 1. See plot; move $\theta=150^\circ$ then $r=3$ to get the point.
Step 2. Use the formulas $x=r\ cos\theta$ and $y=r\ sin\theta$; we have $x=3cos150^\circ =-\frac{3\sqrt 3}{2}$ and $y=3sin150^\circ=\frac{3}{2} $, giving a point $(-\frac{3\sqrt 3}{2}, \frac{3}{2})$
