Question

a trapezoid was transformed on a coordinate grid using the rule (x, y) → (x, -y). which of the following describes this transformation? a. a 90° clockwise rotation about the origin. b. a 180° clockwise rotation about the origin. c. a reflection across the y - axis. d. a reflection across the x - axis.

Explanation:

Step1: Recall transformation rules

In a coordinate - plane, for a point $(x,y)$:

• A $90^{\circ}$ clockwise rotation about the origin has the rule $(x,y)\to(y, - x)$.
• A $180^{\circ}$ clockwise rotation about the origin has the rule $(x,y)\to(-x,-y)$.
• A reflection across the $y$ - axis has the rule $(x,y)\to(-x,y)$.
• A reflection across the $x$ - axis has the rule $(x,y)\to(x, - y)$.

Answer:

D. A reflection across the x - axis.