A linear pair of angles is defined as two adjacent angles that are formed when two lines intersect. The key characteristics of a linear pair are that the angles must be next to each other (adjacent) and their non-common sides form a straight line, which means the angles are supplementary.
To explain further, when two lines cross, they create four angles. If you focus on just two of those angles that share a common ray and are positioned on either side of that ray, you’ve got yourself a linear pair. The main point to remember is that these angles always add up to 180 degrees, making them supplementary.
In summary, the best definition of a linear pair of angles is that they are two adjacent angles formed when two lines intersect, and they add up to 180 degrees.