There is something wrong with this definition for a pair of vertical angles: If and AB CDintersect at point P, then APC and BPD are a pair of vertical angles. Sketch a counterexample to show why it is not correct. Can you add a phrase to correct it?

Mathematics (from Greek μάθημα máthēma, “knowledge, study, learning”) is the study of topics such as quantity (numbers), structure space, and change. There is a range of views among mathematicians and philosophers as to the exact scope anddefinition of mathematics Mathematicians seek out patterns and use them to formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures...