2. Reflections Section 9-1

3. Reflection A reflection is a transformation representing a flip of a figure

4. To abbreviate reflection in line j, we write R j. To abbreviate R j maps P to P’, we write.

5. A reflection in a line is an isometry ( a congruence transformation). Since a reflection is an isometry, it preserves distance and angle measure.

6. It is also possible to reflect an image with respect to a point. Point P is the reflection of R with respect to Q. Therefore, Q is a point of reflection. P Q R

7. Lines and Points of Symmetry Some figures can be folded so that the 2 halves match. The fold is a line of symmetry. For some figures, a point can be found that is a common point of reflection for all points on a figure. This point is called a point of symmetry.

8. 4 lines of symmetry Point of symmetry 1 line of symmetry No point of symmetry

9. Reflections Reflection x-axisy-axisoriginy=x Preimage to Image How to find coordinates Multiply the y-coordinate by -1 Multiply the x-coordinate by -1 Multiply both coordinates by -1 Interchange the x and y coordinates

10. Joke Time Why did the tomato blush? He saw the salad dressing!

11. What did the dog yell when it saw the pieces of a fallen tree? Bark! Bark!