The angle congruent to angle 2 is angle 1 and angle 3.
Angle 1 and angle 2 are supplementary angles, so they add up to 180 degrees. Because angle 1 is 90 degrees, or a right angle, that means angle 2 must also be 90 degrees. This makes them congruent.
because angle 1 and angle 3 are vertical angles, they are congruent, and because angle 1 is congruent to angle 2, then angle 1 is congruent to angle 3.
