Triangle ABC is shown below.
Triangle ABC; line passes through points D, B, and E
Given: ∆ABC
Prove: All three angles of ∆ABC add up to 180°.
The flow chart with missing reason proves the measures of the interior angles of ∆ABC total 180°.
Which reason can be used to fill in the numbered blank space?
Associative Property of Addition
Triangle Exterior Angle Theorem
Angle Addition Postulate
Commutative Property of Addition
