Question

Practice finding reflections.
On a coordinate plane, segment A B goes from (1, 1) to (4, 3) and segment A prime B prime goes from (1, negative 1) to (4, negative 3).

Determine the line of reflection that maps the pre-image segment AB to the image segment A’B’.


x = 0
y = 0
y = x
It cannot be determined.

Answer 1

y = 0

Explanation: Reflecting across y = 0 (the x-axis) sends (x,y) to (x,−y). A(1,1) → (1,−1) and B(4,3) → (4,−3). The midpoints (1,0) and (4,0) lie on y = 0.