Question

△RST is mapped to △R′S′T′ using the rule (x, y)→(x, −y) followed by (x, y)→(3x, 3y) .

Which statement correctly describes the relationship between △RST and △R′S′T′ ?

△RST is not congruent to △R′S′T′ because the rules do not represent a sequence of rigid motions.

△RST is congruent to △R′S′T′ because the rules represent a reflection followed by a rotation, which is a sequence of rigid motions.

△RST is congruent to △R′S′T′ because the rules represent a reflection followed by a translation, which is a sequence of rigid motions.

△RST is congruent to △R′S′T′ because the rules represent a rotation followed by a translation, which is a sequence of rigid motions.

Answer 1

I think it's the first one (NOT CONGRUENT) because a reflection
(y->-y) followed by a dilation (x->3x, y->3y). Reflections and rotations ARE congruent because rigid motions, but dilations/contractions change size, are NOT rigid, and therefore NOT congruent.