angles, bisectors, angle relationships, and how to classify polygons. 1.1 Points, Lines AB or any combination of two of the letters A,C or B in any order. c) Yes, they lie on. If the two endpoints are (-5, 6) and (3, 4), then the midpoint is (-1, 4). -1 is halfway 108◦. = 72. ◦. Example 6: Are ∠CDA and ∠DAB a linear pair?