Answer:
(a) ΔARS ≅ ΔAQT
Explanation:
The theorem being used to show congruence is ASA. In one of the triangles, the angles are 1 and R, and the side between them is AR. The triangle containing those angles and that side is ΔARS.
In the other triangle, the angles are 3 and Q, and the side between them is AQ. The triangles containing those angles and that side is ΔAQT.
The desired congruence statement in Step 3 is ...
ΔARS ≅ ΔAQT