What are adjacent angles?

Adjacent angles are defined as angles that share a common vertex and a common side, while also not overlapping. This means that they are next to each other and together they form a configuration where they can be easily identified on a geometric figure.

For instance, if two angles are formed by two intersecting lines, and they share one side and the point where the lines meet (the vertex), those angles are adjacent. This concept is important in geometry because adjacent angles can be used to analyze the properties and relationships of various geometric shapes and figures.

The other definitions provided do not describe adjacent angles. While congruent angles refer to angles that have the same measure, and complementary angles are two angles that sum up to 90 degrees, neither condition relates to the adjacency of angles in terms of shared sides or vertices. Similarly, angles that sum to 180 degrees could be relevant in other contexts, such as supplementary angles, but do not define adjacency.