Question

Which graph shows the image of the triangle reflected across the line of reflection shown?

On a coordinate plane, a triangle has points (2, 4), (4, 2), (9, 6). A line of reflection is at y = 3.
On a coordinate plane, a triangle has points (negative 1, negative 3), (2, 4), (4, 2).
On a coordinate plane, a triangle has points (1, 4), (4, 2), (2, 0).
On a coordinate plane, a triangle has points (2, 0), (4, 2), (9, negative 2).
On a coordinate plane, a triangle has points (2, 2), (4, 4), (9, 0).

Answer 1

Reflecting (x,y) across y = 3 gives (x, 6 − y).

(2,4) → (2,2); (4,2) → (4,4); (9,6) → (9,0).

So the correct image is the triangle with points (2,2), (4,4), (9,0).