1. Glide Reflections Review Mrs. Erickson

2. Composition of Transformations When two transformations are performed, one following another, that is called a composition of transformations. First you get A’, then you get A’’.

3. Glide Reflections Glide Reflection: A composition of transformations that consist of a line reflection and a translation in the direction of that line (in either order).

4. Glide Reflections y ΔABC: A (1,2) B (5,3) C (3,4) Reflect in y-axis T0,-4 --------------------------- T0,-4 Reflect in y-axis C’ (-3,4) C (3,4) B (5,3) B’ (-5,3) -4 A’ (-1,2) A (1,2) C’’ (-3,0) x B’’ (-5,-1) A’’ (-1,-2)

5. Glide Reflections y ΔPQR: P (2,1) Q (4,1) R (3,4) Reflect across y=x T-3,-3 --------------------------- T-3,-3 Reflect in y-axis R (3,4) Q’ (1,4) -3 R’ (4,3) P’ (1,2) -3 Q’’ (-2,1) P (2,1) Q (4,1) x R’’ (1,0) P’’ (-2,-1) y=x

6. Glide Reflections y ΔABC: A (1,2) B (5,3) C (3,4) Reflect in y-axis T5,-5 C’ (-3,4) C (3,4) 5 B (5,3) B’ (-5,3) A’ (-1,2) A (1,2) -5 x C’’ (2,-1) B’’ (0,-2) Not a glide reflection. The translation is not parallel to the y-axis. A’’ (4,-3)

7. Isometry An isometry is a transformation that preserves distance. Direct isometry: preserves distance and orientation. Opposite isometry: preserves distance but changes the orientation from clockwise to counterclockwise, or counterclockwise to clockwise.

8. Done! Did that horn scare you? … what about now?