1. Mrs. Taormina Geometry C
9-2 Reflections
Mrs. Taormina
Geometry C

2. Reflection We must identify the line of reflection
What do you notice about each corresponding point as it relates to the line of reflection?
All corresponding points are equidistant from the line of reflection.
This means that reflections preserve distance.

3. Let’s Reflect!

4. Let’s Try Another! A B C D B’ C’ A’ D’

5. REFLECTIONS Reflection: <FLIP> 1. 2. Reverses Orientation
Rigid Motion (isometric)

6. Reflecting a figure on the x-axis
( a , b) → (a , -b)
A(-2, 1)  A(-2, -1)
X(1, 3)  X(1, -3)
Y(2, -1)  Y(2, 1)
W(-1, -2)  W(-1, 2)

7. Reflecting a figure on the y-axis
( a , b) → (-a , b)
A(-2, 1)  A(2, 1)
Y(2, -1)  Y(-2, -1)
X(1, 3)  X(-1, 3)
W(-1, -2)  W(1, -2)

8. Reflecting a figure on the origin
( a , b) → (-a , -b)
A(-2, 1)  A(2, -1)
X(1, 3)  X(-1, -3)
Y(2, -1)  Y(-2, 1)
W(-1, -2)  W(1, 2)

9. Reflection on the line y = x
( a , b) → ( b , a )
A(-2, 1)  A(1, -2)
X(1, 3)  X(3, 1)
Y(2, -1)  Y(-1, 2)
W(-1, -2)  W(-2, -1)