When polygon ABCD is reflected across EF, the following is true: For each point A in the preimage and the corresponding point A' in
the image, EF is the perpendicular bisector of AA'.
15-
C'
The following table shows how the coordinates of a preimage
change after being reflected across a certain line.
B В
Line or Point of Reflection
Equation Relating Coordinates
10-
90°
E
90°
across the
-axis
F
across the
-axis
90°
across the line y =
(x, y) = (x,-y)
(x', y) = (-x, y)
(x, y) = (y, x)
(x, y) = (-7, -x)
|(x, y) = (-*, -y)
В,
across the line y =
across the
0
А
0
5
10