Question

Triangle RST was transformed using the rule (x, y) → (–x, –y). The vertices of the triangles are shown.

R (1, 1)
S (3, 1)
T (1, 6) R' (–1, –1)
S' (–3, –1)
T' (–1, –6)
Which best describes the transformation?

The transformation was a 90° rotation about the origin.
The transformation was a 180° rotation about the origin.
The transformation was a 270° rotation about the origin.
The transformation was a 360° rotation about the origin.

Answer 1

The transformation is a 180° rotation about the origin.

Reason: (x, y) → (−x, −y) negates both coordinates, which is the effect of a half-turn (180° rotation) about the origin.