Two angles whose sum is 180 degrees are called what?

Two angles whose sum is 180 degrees are called what?

• A. Complementary angles
• B. Vertical angles
• C. Supplementary angles
• D. Adjacent angles

Answer: (C)

Two angles add to 180 degrees when they fill a straight line. That’s what supplementary angles are: their measures sum to 180. This often happens when the two angles share a vertex and lie on the same straight line, forming a linear pair. Complementary angles sum to 90, vertical angles are the opposite angles formed by intersecting lines (and they’re equal to each other, not about a 180-degree sum), and adjacent angles just share a vertex and a side (they may or may not total 180).

Two angles add to 180 degrees when they fill a straight line. That’s what supplementary angles are: their measures sum to 180. This often happens when the two angles share a vertex and lie on the same straight line, forming a linear pair.

Complementary angles sum to 90, vertical angles are the opposite angles formed by intersecting lines (and they’re equal to each other, not about a 180-degree sum), and adjacent angles just share a vertex and a side (they may or may not total 180).