Question

There is something wrong with this definition for a pair of vertical angles: "If line AB and line CD intersect at point P, then angle APC and angle BPD are a pair of vertical angles.

What is wrong??!?

Answer 1

Well, the only thing I can see "lacking" in the definition is if the intersection P is actually also one of the A,B,C,D points. So you could just say ""If line AB and line CD intersect at point P such that P is different from A, B, C or D, then angle APC and angle BPD are a pair of vertical angles."

Answer 2

Point D and Point C could lie on the same end of the line so that both points are on one side of the intersection point (point P)

Answer 3

It doesn't say that the angles are congruent.