Angles 1 and 2 are less than 90, therefore ACUTE (neither right nor obtuse); they are equivalent because they are across the intersection of 2 lines, called VERTICAL angles; they do not add up to 180, so not supplementary, and not enough info to prove they add up to 90, so not complimentary; not right next to each other (adjacent) making a larger angle.
So the only terms that they are by the proof given are: ACUTE & VERTICAL.
