Triangle ABC is shown below

The flow chart with missing reason proves the measures of the interior angles of triangle ABC total 180.
Which reason can be used to fill in the numbered blank space? Which reason can be used to fill in the numbered blank space?
Angle Addition Postulate
Definition of Complementary Angle
Definition of Supplementary Angles
Substitution

Triangle ABC is shown below The flow chart with missing reason proves the measures of the interior angles of triangle ABC total 180 Which reason can be used to class=