Parallel lines and angles of intersections: ACT Math Practice Question

Try this ACT math practice question on finding the relationship between the angles formed by a line intersecting a pair of parallel lines.

In the figure below, $l \parallel m$ and $m \perp n$. What is $y$ in terms of $x$ ?

1. $\quad x-45$
2. $\quad x-90$
3. $\quad 45-x$
4. $\quad 90-x$
5. $\quad 180-x$

Choice B

Video explanation