Presenter notes: Open by writing all seven names on the board in a long column: complementary, supplementary, adjacent, linear pair, vertically opposite, corresponding, alternate, co-interior. Let the class look at it and feel how much there is to learn. Then say that by the end of the lesson that column will have collapsed into three lines, and that nobody is going to memorise the list. This framing matters, because a student who believes there are eight separate things to learn will study it as vocabulary, and a student who believes there are three will study it as reasoning.