1. Learning Objective
We will determine1 how to use Reflections to draw a preimage and image of a figure on the coordinate plane.
What are we going to do?
What is determine means?_____.
CFU
Activate Prior Knowledge
A reflection can be thought of as folding or "flipping" an object over the line of reflection. Reflection have the same shape and size, but the figures face in opposite directions. The objects appear as if they are mirror reflections, with right and left reversed.
Mirror
Use tracing paper to copy the figure and line l. Then fold the paper to draw and label the image of the figure after a reflection across line l.
Students, you already know how to do Reflection on the paper. Today, we will learn how to do Reflection on the coordinate points.
Make Connection
1 Figure out
Vocabulary

2. Skill Development/Guided Practice
The table summarizes coordinate notation for reflections on a coordinate plane
. D
. E
. F
. G
Pair-Share: How do you reflect a figure?
CFU

3. . . . . 1. Reflect over the x-axis. (-4, 5) (-2, 1) (2, 2) (5, 5)
Skill Development/Guided Practice
A reflection is a transformation that moves a figure, called the preimage, by flipping it across a line. The reflected figure is called the image.
Steps to find Reflection 1 2 3 4
How did I/you know which point to choice?
How did I/you find the reflection type?
How did I/you plot the pre-image points?
CFU 1 2 3
Find the coordinates of the vertices of the preimage
Graph the preimage.
Find the coordinates of the vertices of the image (Apply the Rule)
Graph the Image.
1. Reflect over the x-axis.
(-4, 5)
(-2, 1)
(2, 2)
(5, 5) . . . .

4. 1. Reflect over y = x. preimage image
Skill Development/Guided Practice
A reflection is a transformation that moves a figure, called the preimage, by flipping it across a line. The reflected figure is called the image.
Steps to find Reflection 1 2 3 4
How did I/you know which point to choice?
How did I/you find the reflection type?
How did I/you plot the pre-image points?
CFU 1 2 3
Find the coordinates of the vertices of the preimage
Graph the preimage.
Find the coordinates of the vertices of the image (Apply the Rule)
Graph the Image.
1. Reflect over y = x. preimage image

5. what would the reflection rule be?
Skill Development/Guided Practice
A reflection is a transformation that moves a figure, called the preimage, by flipping it across a line. The reflected figure is called the image.
Steps to find Reflection 1 2 3 4
Find the coordinates of the vertices of the preimage
Graph the preimage.
Find the coordinates of the vertices of the image (Apply the Rule)
Graph the Image.
On your whiteboard:
1. If the preimage was reflected over the y-axis instead of the x-axis,
what would the reflection rule be?
2. List the coordinates of the image if the preimage is reflected over
the y-axis:
3. If the preimage was located completely in Quadrant I, then
reflected once over the x-axis and once over the y-axis,
where would the image be? Explain.

6. What did you learn today about how to use Vector Translation & Reflections to draw a preimage and image of a figure on the coordinate plane.
Word Bank
Vector
Initial Point
Terminal point
Translation
Component Form
Image & Preimage
SUMMARY CLOSURE
Today, I learned how to __________________
______________________________________________________________.

7. Relevance Reason #1: World of Vectors
Denoting both direction and magnitude, vectors appear throughout the world of science and engineering. In sports, a quarterback's pass is a good example, because it has a direction (usually somewhere downfield) and a magnitude (how hard the ball is thrown).
Relevance Reason #2: Know how to find & use Vector will help you do well on tests: (PSAT, SAT, ACT, GRE, GMAT, LSAT, etc..).
Sample Item
Check for Understanding
Does anyone else have another reason why it is relevant to use vector?
Which reason is most relevant to you? Why?