
Reflection Geometry: Line of Reflection and Coordinate Rules
A reflection in geometry flips a figure across a line called the line of reflection. Each point and its image sit the same perpendicular distance from that line, which is the perpendicular bisector of the segment joining them. On a coordinate plane: over the x-axis, (x, y) maps to (x, −y); over the y-axis, (x, y) maps to (−x, y); over y = x, swap to (y, x). Distance and size stay fixed, but the mirror flip reverses orientation.




