Carolina compared her proof to Penn’s work in problem 7-96. Like him, she wanted to prove that if and , then . Unfortunately, her statements were in a different order. Examine her proof below and help her decide if her statements are in a logical order in order to prove that .
Statements
Reasons
and
Given
If lines are parallel, alternate interior angles are equal.
Substitution
If lines are parallel, corresponding angles are equal.
Vertical angles are equal.
Substitution
Is it possible to know that in the 3rd statement? What step is out of order?