ANSWER:
Explanation:
In part 3, we have two angles that add up to 180°, this would be the definition of supplementary angles.
In part 4, since both sums are equal to 180° by transitivity both sums are also equal. This would be the transitivite property of equality.
In part 6, we have the definition of the converse of the corresponding angles theorem which says that If two lines and a transversal form corresponding angles that are congruent, then the lines are parallel.