1. Triangle ABC has vertices A(1, 3), B(–2, –1) and C(3, –2)
Triangle ABC has vertices A(1, 3), B(–2, –1) and C(3, –2). Graph △ABC and its image after the indicated glide reflection. Translation: along 〈2, 0〉 Reflection: in y-axis
Problem of the Day

2. Section 9-5 Symmetry

3. Then Now Objectives You drew reflections and rotations of figures.
Identify line and rotational symmetries in 2D figures.
Identify plane and axis symmetries in 3D figures.

4. Common Core State Standards
Content Standards
G.CO.3 – Given a rectangle, parallelogram, trapezoid, or regular polygon, describe the rotations and reflections that carry it onto itself.
Mathematical Practices
4) Model with mathematics.
8) Look for and express regularity in repeated reasoning.
Common Core State Standards

5. A figure has symmetry if there exists a rigid motion (reflection, translations, rotation, or glide reflection) that maps the figure onto itself.
Vocabulary

7. State whether the figure has line symmetry. Write yes or no
State whether the figure has line symmetry. Write yes or no. Draw all lines of symmetry and state their number.
Example 1

8. State whether the figure has line symmetry. Write yes or no
State whether the figure has line symmetry. Write yes or no. Draw all lines of symmetry and state their number.
Example 1

9. State whether the figure has line symmetry. Write yes or no
State whether the figure has line symmetry. Write yes or no. Draw all lines of symmetry and state their number.
Example 1

11. The number of times a figure maps onto itself as it rotates from 0° to 360° is called the order of symmetry. The magnitude of symmetry (or angle of rotation) is the smallest angles through which a figure can be rotated so that it maps onto itself.
Vocabulary

12. State whether the figure has rotational symmetry. Write yes or no
State whether the figure has rotational symmetry. Write yes or no. Locate the center of symmetry and state the order and magnitude of symmetry.
Example 2

14. State whether each piece of sports equipment appears to have plane symmetry, axis symmetry, both, or neither (ignoring the equipment’s stitching or markings).
Example 3

15. State whether each piece of sports equipment appears to have plane symmetry, axis symmetry, both, or neither (ignoring the equipment’s stitching or markings).
Example 3

16. p.666 #1 – 33 odd
Homework