angle 2 is congruent to angle 3 because 1 and 2 are complementary and 1 and 3 are complementary.
Complementary angles are angles that sum up to 90°. Examples are 30 and 60 , 10 and 80 e.t.c
Since angle ABC is perpendicular, this beans ABC is 90°
therefore ;
angle 1 + angle 2 = 90°
angle 1 and 3 are complementary, this means
angle 1 + angle 3 = 90
Therefore;
angle 1 + angle 3 = angle 1 + angle 2
subtract angle 1 from both sides
angle 3 = angle 2
Therefore, angle 3 and angle 2 are congruent.