By the linear pair theorem, is supplementary to , which means . It is given that , so by the definition of congruent angles, . Using the substitution property of equality, substitute in for to rewrite the previous equation as . Thus is supplementary to by the definition of supplementary angles. By the linear pair theorem, is supplementary to . Since and are supplementary to , then by the congruent supplements theorem, . Use the paragraph proof to complete the two-column proof. What statement and reason belong in line 5?
