Exercise 32 Page 526

According to the Lines Perpendicular to a Transversal Theorem, if two lines are perpendicular to the same line then they are parallel to each other. Therefore, $a$ and $b$ are parallel. Let's illustrate this.

Drawing line $d,$ we know that it is parallel to line $c.$ Since it's parallel to line $c$ we can, by the Perpendicular Transversal Theorem, say that line $d$ is perpendicular to both $a$ and $b.$

As we can see, the figure is a rectangle with sides $x$ and $y.$