Answer:
1.

2. Given
3.
4. Side-Side-Side (SSS) rule of congruency
Explanation:
The two column proof is presented as follows;
Statement
Reason
1.
≅
Given
2.
≅
Given
3.
≅
Reflexive property
4. ΔRST ≅ ΔTUR
SSS rule of congruency

The Side-Side-Side rule of congruency states that if three sides of one triangle are congruent to three sides of another triangle then both triangles are congruent.