Question

Triangles R S T and X Y T are congruent. Triangle R S T is reflected across a line and then rotated at point T to form triangle X Y T.
Is there a series of rigid transformations that could map ΔRST to ΔXYT? If so, which transformations could be used?

No, ΔRST and ΔXYT are congruent but ΔRST cannot be mapped to ΔXYT using a series rigid transformations.
No, ΔRST and ΔXYT are not congruent.
Yes, ΔRST can be reflected across the line containing RT and then rotated about T so that S is mapped to Y.
Yes, ΔRST can be translated so that S is mapped to Y and then rotated about S so that R is mapped to X

Answer 1

Answer: Yes — the third choice.

Reflect across the line containing RT (points R and T lie on that line so R and T stay in place while S goes to the other side), then rotate about T to carry R to X and S to Y. This sequence is a rigid motion sending ΔRST to ΔXYT.