Respuesta :

Answer:

Definition of supplementary angles

Step-by-step explanation:

Supplementary angles or angles on a straight line add up to 180°.

Hope this helps!

Answer:

Substitution

Step-by-step explanation:

Definition of supplementary angles is wrong because supplementary angles are two angles not 3.

Definition of complementary angles is wrong because it means angles that equal to 90 not 180. Plus it means two angles not three.

Angle addition postulate is wrong because it means angles that add up to an another unknown angle. Not angles that add up to 180.