Answer
See below.
Work Step by Step
To convert from polar to rectangular coordinates we use $x=r\cos\theta$ and $y=r\sin\theta$. To convert from rectangular to polar coordinates, we use $r=\pm\sqrt{x^2+y^2}$, $\tan\theta=\frac{y}{x}$, but aware of which quadrant the point lies in.
Hence here the given point in rectangular coordinates: $(4\cos225,4\sin225)=(-2\sqrt2,-2\sqrt2)$
If we have a point $(r,\theta)$, the points $(r,\theta+k360^\circ)$ and $(-r, \theta+180^\circ+l360^\circ)$ with $k,l$ integers will represent the same point. Hence here for $\theta$ to be between $-360^\circ$ and $360^\circ$ we get the following points: $(-4,45^\circ), (4,-135^\circ)$.
