1. In mathematics, a transformation
changes the position or orientation of a
figure.
The resulting figure is the image
of the original figure, called the preimage.
Images resulting from the transformations described in the next slides are congruent to the original figures.

2. Types of Transformations
Translation
The figure slides along a straight line without turning.

3. Types of Transformations
Reflection
The figure flips across a line of reflection, creating a mirror image.

4. Types of Transformations
Rotation
The figure turns around a fixed point.

5. Additional Example 1: Identifying Types of Transformations
Identify each type of transformation. A. B.
The figure flips across the y-axis.
The figure slides along a straight line.

6. Check It Out: Example 1
Identify the type of transformation.

7. Additional Example 2: Graphing Transformations on a Coordinate Plane
Graph the translation of quadrilateral ABCD 4 units left and 2 units down.

8. Write the coordinate of the vertices of the image.
Quadrilateral ABCD
(x – 4, y – 2)
A’B’C’D’
A(1, 3)
B(4, 4)
C(4, 1)
D(1, –1)

9. Reading Math
A’ is read “A prime” and is used to represent the point on the image that corresponds to point A of the original figure

10. Check It Out: Example 2
Graph the translation of quadrilateral ABCD 5 units left and 3 units down. x y A B C 2 –2 4 –4 D

11. Additional Example 3: Graphing Reflections on a Coordinate Plane
Graph the reflection of the figure across the indicated axis. Write the coordinates of the vertices of the image.

12. Additional Example 3 Continued
A. x-axis
Note: The x-coordinates of the corresponding vertices are the same, and the y-coordinates of the corresponding vertices are opposites.

13. Note: The y-coordinates of the corresponding vertices are the same, and the x-coordinates of the corresponding vertices are opposites.
B. y-axis

14. Graph the reflection of quadrilateral ABCD across the x-axis.
Check It Out: Example 3
Graph the reflection of quadrilateral ABCD across the x-axis. x y A B C 2 –2 4 –4 D

15. Additional Example 4: Graphing Rotations on a Coordinate Plane
Triangle ABC has vertices A(1, 0), B(3, 3), C(5, 0). Rotate ∆ABC 180° about the origin. Write the coordinates of the vertices of the image. x y A B C 3 –3
The corresponding sides, AC and AC’ make a 180° angle.
Notice that vertex C is 4 units to the right of vertex A, and vertex C’ is 4 units to the left of vertex A. C’ B’ A’

16. Rotate the graph of quadrilateral ABCD 90° clockwise about the origin.
Check It Out: Example 4
Rotate the graph of quadrilateral ABCD 90° clockwise about the origin. x y A B C 2 –2 4 –4 D

17. Lesson Quiz
1. Identify the transformation.

18. 2. The figure formed by (–5, –6), (–1, –6), and
(3, 2) is translated 6 units right and 2 units up. What are the coordinates of the new figure?

19. 3. Graph the triangle with vertices A(0, 0), B(–3, 0), C(–1, 4)
3. Graph the triangle with vertices A(0, 0), B(–3, 0), C(–1, 4). Reflect ∆ABC across the y-axis and give the coordinates of the vertices of the image.

20. Lesson Quiz for Student Response Systems
1. Identify the transformation.
A. translation
B. reflection
C. rotation
D. none

21. Lesson Quiz for Student Response Systems
2. The figure formed by (–3, 2), (–4, 1), and (–1, –5) is translated 3 units right and 5 units up. What are the coordinates of the new figure?
A. (–6, –3), (–7, –4), (–4, –10)
B. (0, 7), (–7, –4), (2, –10)
C. (0, 7), (–1, 6), (2, 0)
D. (–6, –3), (–1, 6), (–4, 0)