Adjacent angles are two angles having the same vertex and one side in common, with disjoint interiors. If their noncommon sides are opposite rays, the adjacent angles form a linear pair and are supplementary angles.
Adjacent Angles
See also
Angle, Linear Pair, Ray, Side, Supplementary Angles, VertexExplore with Wolfram|Alpha
References
Kirk, D. "Angles." §10.2 in Contemporary Mathematics. Houston, TX: OpenStax, 2023. https://openstax.org/books/contemporary-mathematics/pages/10-2-angles.Cite this as:
Weisstein, Eric W. "Adjacent Angles." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/AdjacentAngles.html