1. Transformations - Reflections
Today’s Lesson:
What:
Transformations - Reflections
Why:
To perform reflections of figures on the coordinate plane.

2. A reflection is a ____________ .
What is a Reflection?
A reflection is a ____________ .
We will reflect figures on the coordinate plane over both the x axis and A AI
flip
y axis.

3. Example 1: Identifying Reflections
Tell whether each transformation appears to be a reflection. Explain. A. B.
No; the image does not
Appear to be flipped.
Yes; the image appears to be flipped across a line..

4. Check It Out! Example 1
Tell whether each transformation appears to be a reflection. a. b.
No; the figure does not appear to be flipped.
Yes; the image appears to be flipped across a line.

5. Reflecting across x-axis
Reflect the following shape across the x-axis
Pre-image Image
M(2, 1)
M’(2, -1)
A(-1, 1)
A’(-1, -1) T H
T(-3, 5)
T’(-3, -5) A M
H(4, 5)
H’(4, -5) A’ M’ T’ H’
What do you notice about
the x and y coordinates
of the pre-image and image
points?

6. Reflect the figure over the “x” axis:
Perform the following reflections:
Reflect the figure over the “x” axis:

7. 2) Reflect the figure over the “y” axis:
Perform the following reflections:
2) Reflect the figure over the “y” axis:

8. 3) Reflect the figure over the “x” axis:
Perform the following reflections:
3) Reflect the figure over the “x” axis:

9. 4) Reflect the figure over the “y” axis:
Perform the following reflections:
4) Reflect the figure over the “y” axis:

10. REFLECTIONS
When you reflect across the x-axis, the x-coordinate remains the same, but the y-coordinate is transformed into its opposite.
The reflection of the point (x,y) across the x-axis is the point (x, -y).
When you reflect across the y-axis, the y-coordinate remains the same, but the x-coordinate is transformed into its opposite.
The reflection of the point (x,y) across the y-axis is the point (-x, y).

11. Writing Equations
Remember equations for horizontal lines:
y = 2 is horizontal line crossing y-axis at 2
y = –4 is horizontal line crossing y-axis at 4
y=2
y =–4

12. Writing Equations
Remember equations for vertical lines:
x = 2 is vertical line crossing x-axis at 2
x = –4 is vertical line crossing x-axis at –4
x =–4
x=2

13. Reflections classwork
Name:__________________________________________________________Date:_____/_____/__________
Reflections classwork

16. Math-8 NOTES What is a Reflection?? A reflection is a ____________ .
DATE: ______/_______/_______
What: Transformations - Reflections
Why: To perform reflections of figures on the coordinate plane.
NAME:
What is a Reflection??
A reflection is a ____________ .
We will reflect on the coordinate plane over both the x axis and the ___________________________ . A AI
Perform the following reflections:
Reflect the figure over the ) Reflect the figure over the
“x” axis: “y” axis:
Reflect the figure over the ) Reflect the figure over the
“x” axis: “y” axis:

17. Reflections classwork
Name:__________________________________________________________Date:_____/_____/__________
Reflections classwork

20. “Reflections” Practice/ homework
Name:________________________________________________________Date:_____/_____/__________
Math-8
“Reflections” Practice/ homework
1) Reflection across the x axis:
2) Reflection across the y axis:
3) Reflection across the y axis:
4) Reflection across the x axis:
5) Reflection across the x axis:
6) Reflection across the y axis:

21. 7) Reflection across the x-axis:
8) Reflection across the y-axis:
9) Write a rule to describe the below reflection: