When are supplementary angles congruent?

Question

anonymous · Answer

The only way to be adjacent and supplementary would be two angles on a straight line: 

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The two angles on top are adjacent and supplementary. Therefore, they could be congruent if the the line in between them was perpendicular to the straight line, and so each angle was 90º ... otherwise, they wouldn't be congruent

anonymous · Answer

thank u that helps

anonymous · Answer

no problem.

anonymous · Answer

Supplementary angles are congruent if and only if they are both equal to 90 degrees. This is because 2x = 180 (x being your angle) divide by two on both sides to get x = 90. Hope this helps!