Answer:
See proof
Step-by-step explanation:
We have that [tex]\angle 1 + \angle 2 = 90^{\circ}[/tex] because [tex]\angle ABC[/tex] is [tex]\perp[/tex].
We have that [tex]\angle 1 + \angle 3 = 90^{\circ}[/tex] because [tex]\angle 1[/tex] and [tex]\angle 2[/tex] are complementary.
We have that [tex]\angle 1 + \angle 2 = \angle 1 + \angle 3[/tex] because we can set the two equations equal to each other.
We have that [tex]\boxed{\angle 2 = \angle 3}[/tex] because we subtract [tex]\angle 1[/tex] from both sides.