1. 9.2 Properties of Reflections
How do you describe the properties of reflection and their effect on the congruence and orientation of figures?
Reflections keeps the size and shape, but not the orientation!

2. Reflection Vocabulary
flips
Reflection – a transformation that ___________ a figure across a line
That line is called ____________________.
Once reflected across the _________ and the ____________, each vertice of the image is the _________ distance from the line of reflection.
line of reflection
x-axis
y-axis
same

3. Properties of Reflections
NOT
When you reflect an image across the coordinate plane axis, it does ______ change the ___________ or _____________, but it does change the ______________ of the shape to a mirror image of the pre-image (the way the shape look compared from the pre-image)
With a reflection transformation angle measures __________________
With a reflection transformation side measures ___________________
size
shape
orientation
keeps congruency
keeps congruency

4. Rules for algebraically reflecting shapes
vertice
Identify the coordinate of each _________________.
When reflecting a shape across the ________________, change the ______ of the ________________.
Example: ( 0, 3 )
Example: (-3,-8)
x-axis
sign
y-value
(0,-3)
y-axis
sign
x-value
(3,-8)

5. Draw the figure. Then draw the described reflection
Reflect across the x-axis, so the ____________ will change signs.
W (-5,2) W’
X (3,0) X’
Y (-2,-5) Y’
Size Change? ____
Shape Change? ____
Orientation ? _____
y-values
(-5,-2)
(3,0)
(-2,5) No No
Yes

6. Draw the figure. Then draw the described reflection
Reflect across the y-axis, so the ____________ will change signs.
G(3,-3)
H (-5,-1)
Y (-4,3)
K (2,2)
Size Change? ____
Shape Change? ____
Orientation ? _____
x-values
(-3,-3)
(5,-1)
(4,3)
(-2,2) No No
Yes

7. Since the new x-values are opposite from the pre-image, the size and shape of the image stayed the same, but the orientation changed.
According to the new image coordinates, which axis did the pre-image reflect across?

8. Double-Prime
Prime
Pre-Image

9. Double-Prime
Prime
Pre-Image