ADJACENT ANGLE -
Adjacent angles are two angles that share a common arm (side) and a common vertex, yet do not overlap. In other words, they are side by side and have a common side. The sum of adjacent angles always equals the total angle formed by both angles.
On the other way we can say that - Two angles are called adjacent angle if they have a common vertex, a common arm and their non-common arms lie on either side of common arm.
If you have an angle formed by two rays or line segments, and you draw another angle next to it, sharing one side, then these two angles are considered adjacent.
For example, consider the angle formed by rays AB and BC. If you draw another angle next to it, say formed by rays BC and CD, with BC as the common side, then the angles ∠ABC and ∠BCD are adjacent angles.
In mathematical terms, if ∠ABC and ∠BCD are adjacent angles, then the sum of their measures (∠ABC + ∠BCD) is equal to the measure of the entire angle formed by rays AB and CD.
Adjacent angles play a crucial role in geometry, and their properties are often used in solving problems involving angles and geometric figures.