if two lines are not right angles are they perpendicular
If two lines are perpendicular, then they meet to form. right angles. Theorem 1.7.1: If two lines meet to form a right angle, then these lines are perpendicular. âif and only ifâ. âiffâ. Theorem 1.7.2: If two angles are complementary to the same angle (or to. congruent angles) then these angles are congruent.