Apply geometric motions to reflect figures. Brinda reflects point T over a line of reflection, resulting in point T′ . If points T and T′ have the same x-coordinate, what must be true?

Question

A. The line of reflection is vertical.
B. The line of reflection is horizontal.
C. The line of reflection is the y-axis.
D. The line of reflection is the x-axis.

Answer 1

If points T and T′ have the same x-coordinate after reflecting point T over a line of reflection, it means that the reflection does not alter the x-coordinate of point T.

In this case, the line of reflection must be a horizontal line. When a point is reflected over a horizontal line, its x-coordinate remains the same, while its y-coordinate changes. Therefore, the correct answer is:

B. The line of reflection is horizontal.