To answer this question we will use the following diagram as reference:
Given that angles B and D are perpendiculars, l and m are parallel, therefore angles C and D have to be equal given that they are alternate interior angles.
Therefore, by the AAA criteria, the given triangles are similar.
Now, since the triangles are similar, we know that:
Multiplying the above equation by 7.5, we get:
Finally, simplifying the above result, we get:
Answer: