Question: do adjacent angles have to be congruent?
Answer: Vertical angles are always congruent, which means that they are equal. Adjacent angles are angles that come out of the same vertex. ... Corresponding angles are congruent. All angles that have the same position with regards to the parallel lines and the transversal are corresponding pairs e.g. 3 + 7, 4 + 8 and 2 + 6.