Question

triangle def is congruent to △def by the sss theorem. which single rigid transformation is required to map △def onto △def?
○ dilation
○ reflection
○ rotation
○ translation

Explanation:

A reflection is a rigid transformation that flips a figure over a line. In this case, since the triangles are congruent by SSS and we need to map one onto the other, a reflection (as dilation changes size, rotation would turn around a point, and translation would slide without flipping) is the correct transformation.

Answer:

reflection