A pair of supplementary angles are angles that together equal 180. A pair would be 2,3 or 9,2 etc. if m1 is 75 then 10 would be 105 because they're supplementary. Vertical angles would be 9,3 or 5,7. They're across from eachother. It would be perpendicular to line segment BA, because the angle would have to be 90 degrees to a straight line.