Given: angle 2 and angle 3 are a linear pair. angle 3 and angle 4 are a linear pair. prove angle 2 is congruent to angle 4. 1. angle 2 and angle 3 are a linear pair. angle 3 and angle 4 are a linear pair. reason: given 2. angle 2 and angle 3 are supplementary. angle 3 and angle 4 are supplementary. reason: ? 3. angle 2 is congruent to angle 4. reason: ?