In △ABC, m∠A=50∘, m∠B=60∘, and m∠C=70∘. If △ABC is rotated 90∘ counterclockwise to △XYZ, what is the measure of angle Z?

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x

the graph line crosses the x axis at both -6 and -2, so the answer would be the second one.