8th Grade · Geometry

Axis of Reflection

8.G.A.2

Definition

The line over which a figure is reflected, acting as a mirror. Each point and its image are equidistant from this line on opposite sides.

Examples

  • Reflecting over the x-axis: (x,y) → (x,-y).
  • Reflecting over the y-axis: (x,y) → (-x,y).

Key rule

Every point and its image are the same distance from the axis, on opposite sides.

Memory hook

The mirror line the figure flips across.