Question

what are supplementary angles?
angles that are equal to each other
angles that are opposite of each other when lines intersect
angles that add up to 180°
angles that add up 90°

Explanation:

Step1: Recall the definition of supplementary angles

Supplementary angles are defined as two angles whose sum is 180 degrees.

Step2: Analyze each option

• Option A: Angles that are equal to each other are called congruent angles, not supplementary angles.
• Option B: Angles that are opposite of each other when lines intersect are called vertical angles, not supplementary angles.
• Option C: This matches the definition of supplementary angles.
• Option D: Angles that add up to 90° are called complementary angles, not supplementary angles.

Answer:

C. Angles that add up to 180°