Answer: Vertical angles are congruent.
Explanation:
In the given picture, NS and RT are intersecting line segments, intersects at point Q.
We know that when two lines intersect to make an cross, angles on opposite sides of the cross are called vertical angles. These angles are equal by the theorem that says Vertical angles are congruent.
⇒∠NQT ≅ ∠SQR
Therefore, the reason that justifies the step 2 :- ∠NQT ≅ ∠SQR is "Vertical angles are congruent" in the proof.