Question

These are two angles that add up to 180° that share a common vertex. What do you call these angles?

Answer 1

• linear angles

• supplementary angles (all linear angles are supplementary)

Explanation:

If the angles share a side and are measured in opposite directions from that side, the non-common edges of these angles form a straight line, so these angles are sometimes called "linear" angles.

Since their sum is 180°, they are always "supplementary" angles. (Supplementary angles need not share a vertex or a side.)