Final answer:
To prove triangle congruence with SAS, two sides and the included angle must be identical in both triangles. Although reflections or rotations naturally result in congruent triangles, SAS specifically requires proof of two congruent sides and the included angle. Therefore, any pairs that can demonstrate these criteria will suffice for SAS congruence.
Step-by-step explanation:
The question asks us to determine which pair of triangles can be proven congruent by the Side-Angle-Side (SAS) postulate. To use SAS, we need to identify two pairs of sides that are equal in length and the angle between those sides also equal in the pair of triangles being compared. When a triangle is reflected across a line or rotated 90 degrees, if the reflection or rotation is done correctly, the triangles will be congruent. In both the given cases -- reflection and rotation -- the corresponding sides and angles in the triangles will remain equal.
However, to prove congruence specifically through SAS, you need to apply it to two different triangles where you can definitively show that two sides and the included angle are identical in both triangles. Reflection or rotation are transformations that show congruence but don't usually require the use of the SAS postulate because congruence is inherent in the properties of these transformations. Nonetheless, if you have two triangles that happen to be reflected or rotated, and you can show that two sides and the included angle are equal for both triangles, you would indeed use SAS as your proof of congruence.