Lines a and b are intersecting lines. Congruent Angle Theorems: Vertical Angles Supplemental Angle Theorems: Linear Pair Theorems (form straight line): Adjacent Angles at Point E Move one slider at a time, make observations Congruent Angles should be equal in size. The Supplemental Angles/Linear Pairs should add to be 180°.
Points A, B, C, and D can be moved by the user to change the orientation of the intersecting lines. Points must stay to the same side of Point E for the demonstration to works.