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

Yes — the correct choice is: "Yes, ΔRST can be reflected across the line containing RT and then rotated about T so that S is mapped to Y."

Reason: reflecting across line RT fixes R and T and sends S to its mirror image S'. A rotation about T can then carry S' to Y (and carry R to X). Those two rigid motions (reflection across RT, then rotation about T) map ΔRST onto ΔXYT.