Which angle property defines two angles whose sum is 180 degrees?

The property that defines two angles whose sum is 180 degrees is known as supplementary angles. This means that if you have two angles and when you add their measures together, the total is exactly 180 degrees, they are classified as supplementary. This property is particularly useful in various geometric contexts, such as in parallel lines crossed by a transversal, where consecutive interior angles are supplementary.

In contrast, adjacent angles are angles that share a common side and vertex but do not necessarily have their angle measurements summing to 180 degrees. Complementary angles, on the other hand, are defined as two angles that sum to 90 degrees. Vertical angles are formed when two lines intersect and are opposite each other, and they are always equal in measure, but they do not imply a sum of 180 degrees. Therefore, the correct identification of the angles that sum to 180 degrees is specifically attributed to supplementary angles.