Answer: D. SSS congruence theorem
Step-by-step explanation:
In the given proof we have in ΔABC ≅ ΔCDA
AB ≅ CD; BC ≅ DA [ opposite sides of a parallelogram are ≅]
AC ≅ AC [ reflexive property]
Therefore by SSS postulate of congruence ΔABC ≅ ΔCDA .
- The SSS postulate says that if all the three sides of a triangle is equal to all the three sides of another triangle then the triangles are said to be congruent.
