In geometry, adjacent angles, often shortened as adj. ∠s, are angles that have a common ray coming out of the vertex going between two other rays, with no overlap of the regions "enclosed" by the two angles. In other words, they are angles that are side by side, or adjacent.
A pair of angles is complementary if the sum of their measures is 90°.
A pair of angles is supplementary if the sum of their measures is 180°.
An angle with a ray connected to a common point down the center. In geometry, two angles are adjacent angles if they share a common vertex and side, but have no common interior points.