Line+of+Reflection



Definition: A reflection is an isometry where if l is any line and P is any point not on l, then rl(P) = P' where l is the perpendicular bisector of and if  then rl(P) = P

A line reflectioncreates a figure that is congruent to the original figure and is called an isometry(a transformation that preserves length). Since naming the figure in a reflection requires changing the order of the letters, a reflection is more specifically called a non-direct or opposite isometry. Remember that a reflection is a flip. Under a reflection, the figure does not change size.

1. distance (lengths of segments are the same) 2. angle measures (remain the same) 3. parallelism (parallel lines remain parallel) 4. collinearity (points stay on the same lines) 5. midpoint (midpoints remain the same in each figure) -- 6. orientation (lettering order NOT preserved. Order is reversed.) || A transformation where every point on a line segment appears an equal distance on the other side of a given line - the line of reflection. [|Click here if you need further explanation]
 * Properties preserved (invariant) under a line reflection: