Which are the parallel lines?
I prove that $a$ and $b$ are parallel but can't prove that $c$ and $d$ are parallel. The angles, which are $135^o$ and $45^o$ are alternate angles.They aren't equal , so $c$ isn't parallel to $d$ but the answer is that $c$ is parallel to $d$. Am I right that they aren't?
Edit: They are a little inclined like these: