1. 9.3 Perform Reflections P 580 With row partners
Must complete STEPS 1,2 and 3
Must answer DRAW CONCLUSIONS questions 1-5
Have 15 minutes to finish.

2. Vocab
Reflection – a transformation that uses a line like a mirror to reflect an image.
Line of reflection – the mirrored line
THEOREM 9.2 Reflection Theorem – a reflection is an isometry

3. Graphing reflections
The vertices of ABC are A(2,4), B(6,3) and C(3,2). Graph the reflection of ABC described.
In the line n: x=1

4. Graphing reflections
The vertices of ABC are A(2,4), B(6,3) and C(3,2). Graph the reflection of ABC described.
In the line n: x=1

5. Graphing reflections
The vertices of ABC are A(2,4), B(6,3) and C(3,2). Graph the reflection of ABC described.
In the line n: x=1
In the line m: y=3

6. Graphing reflections
The vertices of ABC are A(2,4), B(6,3) and C(3,2). Graph the reflection of ABC described.
y = 5

7. Graphing reflections
The vertices of ABC are A(2,4), B(6,3) and C(3,2). Graph the reflection of ABC described.
y = 5
x = -2

8. Graphing reflections
The vertices of ABC are A(2,4), B(6,3) and C(3,2). Graph the reflection of ABC described.
y = 5
x = -2
y = -1

9. More reflections
The endpoints of FG are F(-2,1) and G(2,3). Reflect the segment in the line y = x. Graph FG and its image.

10. Coordinate Rules for Reflections
If (a,b) is reflected in the x-axis, its image is the point (a,-b).
If (a,b) is reflected in the y-axis, its image is the point (-a,b)
If (a,b) is reflected in the line y = x, its image is the point (b,a)
If (a,b) is reflected in the line y = -x, its image is the point (-b, -a)

11. Graph one more reflection y = -x
Graph ABC with vertices A(1,3), B(4,4), and C(3,1). Reflect ABC in the lines y = -x.

12. Using matrix multiplcation
You can use a matrix to find the reflection in the x and y axis.
Write the reflection matrix to the LEFT of the polygon matrix, then multiply.
Reflection in the x-axis −1
Reflection in the y-axis −

13. Matrix Mr. Anderson
The vertices of DEF are D(2,3), E(4,4) and F(5,1). Find the reflection of DEF in the y-axis using matrix multiplication. Graph DEF and its image.