What is the reason for statement 7 of the two-column proof? a) angle addition postulate b) linear pair postulate c) ruler postulate d) angle congruence postulate given: ∠a and ∠b are supplementary. m∠a=90° prove: ∠a≅∠b

     Statements                                                                                               Reason

1. and are supplementary                    Given

2.                Def of supplementary angles

3.                                                                  Given

4.               Substitution property of Equality

5.                                Subtraction property of Equality

6.                           Substitution property of Equality

7.                                 Angle congruence postulate

When the measures of two angles are equal, then the angles are congruent by Angle congruence postulate.

more detail

step-by-step explanation:

m∠a is 90°

m∠b is 40°