a.) Vertical angles are pairs of opposite angles made by intersecting lines. An example of a pair of vertical angles in the given figure is Angle 3 and Angle 2.
They are opposite angles made by intersecting lines l and n.
b.) Linear pairs are adjacent angles that make a total of 180 degrees when their measures added up.
From the figure, Angle 3 and Angle 1 is a linear pair. The same goes for Angle 3 and Angle 4.
c.) Congruent angles and are angles that have the same/equal measures. One way of looking for congruent pairs of angles is looking for vertical angles.
Vertical Angle Theorem states that if two (2) angles are vertical then these angles are congruent.
Angle 3 and Angle 2 is a pair of congruent angles.
Angle 7 and Angle 6 are also vertical angles and therefore congruent pairs.