1. Algebra 1 Notes Lesson 4-2: Transformations on the Coordinate Plane

2. Mathematics Standards
Number, Number Sense and Operations: Demonstrate fluency in computations using real numbers.
Geometry and Spatial Sense: Identify the reflection and rotation symmetries of two- and three-dimensional geometric figures.
Geometry and Spatial Sense: Perform reflections and rotation using compass and straightedge constructions and dynamic geometry software.

3. Mathematics Standards
Geometry and Spatial Sense: Derive coordinate rules for translations, reflections and rotations of geometric figures in the coordinate plane.
Geometry and Spatial Sense: Show and describe the results of combinations of translations, reflections and rotations (compositions).
Geometry and Spatial Sense: Analyze two-dimensional figures in a coordinate plane.

4. Vocabulary Transformation – Movement of figures
Preimage –image before a transformation
Image – Image after a transformation

5. We will always flip figures over the x-axis or y-axis
Reflection
A figure is flipped over a line.
We will always flip figures over the x-axis or y-axis

6. Translation A figure is slid in any direction.
To translate a point by an ordered pair (a, b), add a to the x-coordinate and b to the y-coordinate. You can also count on a graph.

7. Dilation A figure is enlarged or reduced.
To dilate a figure by a scale factor k, multiply both coordinates by k.
If k > 1, the figure is enlarged.
If k < 1, the figure is reduced.

8. Rotation A figure is turned around a point.
To rotate a figure 90º counterclockwise about the origin, switch the coordinates of each point and then multiply the new first coordinate by -1.
To rotate a figure 180º about the origin, multiply both coordinates of each point by -1.

9. Example 1
Identify each transformation. a)

10. Example 1
Identify each transformation.
a) translation b)
dilation

11. Begin Walkthrough