1. Splash Screen

2. Main Idea and Vocabulary Example 1: Real-World Example
Example 4: Reflect a Figure Over the x-axis
Example 5: Reflect a Figure Over the y-axis
Lesson Menu

3. Identify figures with line symmetry and graph reflections on a coordinate plane.
line of symmetry
reflection
line of reflection
Main Idea/Vocabulary

4. Determine whether the figure has line symmetry
Determine whether the figure has line symmetry. If so, copy the figure and draw all lines of symmetry.
Answer: This figure has line symmetry. There are two lines of symmetry.
Example 1

5. S Determine whether the figure has line symmetry.
A. one line of symmetry
B. two lines of symmetry
C. three lines of symmetry
D. no line of symmetry
Example 1

6. Answer: This figure has line symmetry. There is one line of symmetry.
Determine whether the figure has line symmetry. If so, copy the figure and draw all lines of symmetry.
Answer: This figure has line symmetry. There is one line of symmetry.
Example 2

7. C. three lines of symmetry D. no line of symmetry
Determine whether the figure has line symmetry. If so, copy the figure and draw all lines of symmetry.
A. one line of symmetry
B. two lines of symmetry
C. three lines of symmetry
D. no line of symmetry
Example 2

8. Answer: This figure does not have line symmetry.
Determine whether the figure has line symmetry. If so, copy the figure and draw all lines of symmetry.
Answer: This figure does not have line symmetry.
Example 3

9. C. three lines of symmetry D. no line of symmetry
Determine whether the figure has line symmetry. If so, copy the figure and draw all lines of symmetry.
A. one line of symmetry
B. two lines of symmetry
C. three lines of symmetry
D. no line of symmetry
Example 3

10. Reflect a Figure Over the x-axis
Quadrilateral QRST has vertices Q(–1, 1), R(0, 3), S(3, 2), and T(4, 0). Graph the figure and its reflected image over the x-axis. Then find the coordinates of the reflected image.
Example 4

11. Reflect a Figure Over the x-axis
Plot the vertices and connect to form the quadrilateral QRST.
The x-axis is the line of reflection. So, the distance from each point on quadrilateral QRST to the x-axis is the same as the distance from the x-axis to quadrilateral QRST.
Answer: Q(–1, –1) R(0, –3) S(3, –2) T(4, 0)
Example 4

12. A. A(–2, –3), B(–5, –1), C(–3, 3), D(–1, 2)
Quadrilateral ABCD has vertices A(–3, 2), B(–1, 5), C(3, 3), and D(2, 1). Find the coordinates of the reflected image over the x-axis.
A. A(–2, –3), B(–5, –1), C(–3, 3), D(–1, 2)
B. A(0, 2), B(–1, 3), C(–2, 1), D(–4, 5)
C. A(–3, –2), B(–1, –5), C(3, –3), D(2, –1)
D. A(1, –3), B(–2, 4), C(3, –2), D(0, 0)
Example 4

13. Reflect a Figure Over the y-axis
Triangle XYZ has vertices X(1, 2), Y(2, 1), and Z(1, –2). Graph the figure and its reflected image over the y-axis. Then find the coordinates of the reflected image.
Example 5

14. Reflect a Figure Over the y-axis
Plot the vertices and connect to form the triangle XYZ.
The y-axis is the line of reflection. So, the distance from each point on triangle XYZ to the y-axis is the same as the distance from the y-axis to triangle XYZ.
Answer: X(–1, 2), Y(–2, 1), Z(–1, –2)
Example 5

15. Triangle QRS has vertices Q(3, 4), R(1, 0), and S(6, 2)
Triangle QRS has vertices Q(3, 4), R(1, 0), and S(6, 2). Find the coordinates of the reflected image over the y-axis.
A. Q(–2, 3), R(0, 1), S(–5, 1)
B. Q(3, –4), R(1, 0), S(6, –2)
C. Q(4, 3), R(0, 1), S(2, 6)
D. Q(–3, 4), R(–1, 0), S(–6, 2)
Example 5

16. End of the Lesson