what else would need to be congruent to show that abc=def by the AAS THEORM?
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Answer: A. AC≅DF
Step-by-step explanation:
The AAS theorem says that if any two angles and any non-included side of a triangle are congruent to two angles and any non-included side of other triangle then the triangles are congruent.
In the given figure we have ΔABC and ΔDEF, in which
∠A≅∠D
∠B≅∠E
To prove these triangles congruent by AAS theorem , we need one pair of non included side.
i.e. it can be AC≅DF or BC≅EF
AC≅DF is given in the option .
Hence, option A is correct.