Question

the triangles are congruent by the sss congruence theorem. which rigid transformation(s) can map △abc onto △dec? reflection, then rotation reflection, then translation rotation, then translation rotation, then dilation

Explanation:

Step1: Recall rigid - transformation types

Rigid transformations are reflection, rotation and translation. Dilation is not a rigid - transformation as it changes the size of the figure.

Step2: Analyze the orientation and position

First, a rotation can be used to align the general orientation of $\triangle ABC$ with $\triangle DEC$. Then, a translation can be used to move $\triangle ABC$ to exactly overlap $\triangle DEC$.

Answer:

rotation, then translation