1. Lesson 11.4 Translations and Reflections

2. Translation - Each point of a figure is moved in the same distance in the same direction (sometimes called as slide).
Image- the figure you get after the transformation . The translation of A to its image is A’.

3. Example of Translation

4. Example of Translation

5. Notation

6. A point and its image after a translation are given
A point and its image after a translation are given. Write a rule to describe the translation
A(9,-4), A’(2,1)
B(-3, 5), B’(-5,-3)

7. -4 Understanding Translation
The triangle below is translated 5 units right and
4 units down. Describe the translation below using
a coordinate table.
Coordinate Table y x D C E x y
x+5
y-4 C -5 1 -3 +5 D -2 4 3 -4 E 2 5 -2

8. Reflection
Mirror image either over the x or y axis

9. Rule for Line Reflection Over Y-axis

10. Line Reflections Coordinate Notation x y -x y -5 4 5 4 -5 1 5 1 -1 1 1
Line Reflection - Reflection occurs when points are redrawn across a line of symmetry at equal distance. y x
Coordinate Notation A B C
“Opposite of” x y -x y -5 4 5 4 -5 1 5 1 -1 1 1 1
Reflect over Y-AXIS (-x, y) – opposite of x
Reflect over X-AXIS (x, -y) – opposite of y

11. Rule for Line Reflection over x-axis

12. Points L(-3,2), M(3,1), and N(-2,-2) are the vertices
of a triangle. If LMN is reflected over the x-axis,
what are the coordinates of its image?
Coordinate Notation y x L M N

13. Homework
Page (2-16) even