Adjacent angles can be stated as the two angles which have a common vertex and a common side. The common vertex and the common side does not overlap each other.  The two angles have a common side as well as a common vertex. The word adjacent itself means neighboring. It means angles are placed next to each other, but the main rule is that do not overlap each other. It can be stated that if two adjacent angles form a right angle that is 90 degrees then it is termed as complementary angles. However, when the two adjacent angles form 180 degrees then it is known as the supplementary angles.

From the above shown figure it can be easily stated that O is the common vertex for both the sides and angles. Ob is the common side and angle Oab and angle Oad are the adjacent angle. They are angles which are placed just next to each other, they share common point which is known as the vertex, they share a common side and they do not overlap each other. They share a common point but they are not supposed to share the same interior points. It is also used in the case of polygons, where two interior angles are referred as the interior angles of the polygons. The two interior angles of the polygons are the adjacent angles of the polygons. The word adjacent denotes next to each other. When an angle share side but not a common vertex then it is not termed as an adjacent angle. on the other hand, if they share a common vertex but not a common side than also it is not an adjacent angle. The adjacent angles cannot overlap each other. A linear pair is also an adjacent angles having sides which are not common and forms the opposite rays. In case where two angles are forming linear pair it must be supplementary. A linear pair always forms a straight angle with a 180 degree. in case where two congruent angles form a linear pair the angles are supposed to be right angles, in that case each angle is supposed to be 90 degrees. In case of angles there are variety of pairing such as the adjacent angle, the linear pair, the vertical angles, the alternate angles and so on. It is observed that when straight lines intersect each other it gives rise to adjacent angles. It is observed that when two straight lines intersect each other, it gives rise to 4 pairs of adjacent angles. The two adjacent angles are adding up to the 180 degree and which is supplementary to each other. It is observed that each pair of angles are supplementary. The ray which is share between the adjacent angle must be a common ray. However adjacent angles differ from all the other angles. Angles can be interior, exterior, corresponding angles as well as congruent angles. There are certain rules and criteria for all the angles so that it can be easily differentiated from one another.