Math Homework. Do It Faster, Learn It Better.
Vertical Angles Theorem
Theorem:Vertical anglesare alwayscongruent.
In the figure,and.
Proof:
form alinear pair, so by theSupplement Postulate, they aresupplementary. That is,
.
form a linear pair also, so
.
Subtractingfrom both sides of both equations, we get
.
Therefore,
.
You can use a similar argument to prove that.