Splash Screen

Lesson Menu Five-Minute Check (over Lesson 9–4) NGSSS Then/Now New Vocabulary Key Concept: Line Symmetry Example 1:Real-World Example: Identify Line Symmetry Key Concept: Rotational Symmetry Example 2:Identify Rotational Symmetry Key Concept: Three-Dimensional Symmetries Example 3:Three-Dimensional Symmetry

Over Lesson 9–4 A.A B.B C.C D.D 5-Minute Check 1 Triangle XYZ has vertices X(–3, 1), Y(–4, 5), and Z(0, 5). Graph ΔXYZ and its image after the indicated glide reflection. Translation: along,Reflection: in x-axis A.B. C.D.

Over Lesson 9–4 A.A B.B C.C D.D 5-Minute Check 2 Triangle XYZ has vertices X(–3, 1), Y(–4, 5), and Z(0, 5). Graph ΔXYZ and its image after the indicated glide reflection. Translation: along, Reflection: in y-axis A.B. C.D.

Over Lesson 9–4 A.A B.B C.C D.D 5-Minute Check 3 A.length B.angle measure C.orientation D.parallel lines Which of the following characteristics is not preserved under a glide reflection?

NGSSS LA The student will relate new vocabulary to familiar words. MA.912.G.2.4 Apply transformations to polygons to determine congruence, similarity, and symmetry. Know that images formed by translations, reflections, and rotations are congruent to the original shape. Create and verify tessellations of the plane using polygons.

Then/Now You drew reflections and rotations of figures. (Lessons 9–1 and 9–3) Identify line and rotational symmetries in two-dimensional figures. Identify line and rotational symmetries in three-dimensional figures.

Vocabulary symmetry line symmetry line of symmetry rotational symmetry center of symmetry order of symmetry magnitude of symmetry

Concept

Example 1 Identify Line Symmetry A. KALEIDOSCOPES State whether the object appears to have line symmetry. Write yes or no. If so, draw all lines of symmetry, and state their number. Answer: yes; 7 lines of symmetry

Example 1 Identify Line Symmetry B. KALEIDOSCOPES State whether the object appears to have line symmetry. Write yes or no. If so, draw all lines of symmetry, and state their number. Answer: no

Example 1 Identify Line Symmetry C. KALEIDOSCOPES State whether the object appears to have line symmetry. Write yes or no. If so, draw all lines of symmetry, and state their number. Answer: yes; 5 lines of symmetry

A.A B.B C.C D.D Example 1 A.yes; 1 line B.yes; 2 lines C.yes; 3 lines D.no A. State whether the figure appears to have line symmetry. Write yes or no. If so, state their number.

A.A B.B C.C D.D Example 1 A.yes; 1 line B.yes; 2 lines C.yes; 4 lines D.no B. State whether the figure appears to have line symmetry. Write yes or no. If so, state their number.

A.A B.B C.C D.D Example 1 A.yes; 1 line B.yes; 2 lines C.yes; 4 lines D.no C. State whether the figure appears to have line symmetry. Write yes or no. If so, state their number.

Concept

Example 2 Identify Rotational Symmetry A. State whether the figure has rotational symmetry. Write yes or no. If so, locate the center of symmetry, and state the order and magnitude of symmetry. Answer: Yes the star has order 5 rotatonal symmetry and magnitude 360 ÷ 5 = 72°. The center of the star is the center of rotation.

Example 2 Identify Rotational Symmetry B. State whether the figure has rotational symmetry. Write yes or no. If so, locate the center of symmetry, and state the order and magnitude of symmetry. Answer: The propeller has order 3 rotational symmetry and magnitude 360 ÷ 3 = 120°. The center of the propeller is the center of rotation.

Example 2 Identify Rotational Symmetry C. State whether the figure has rotational symmetry. Write yes or no. If so, locate the center of symmetry, and state the order and magnitude of symmetry. Answer: The gear has order 8 rotational symmetry and magnitude 360 ÷ 8 = 45°. The center of the gear is the center of rotation.

A.A B.B C.C D.D Example 2 A.Yes, order 8 and magnitude 45° B.Yes, order 4 and magnitude 90° C.Yes, order 4 and magnitude 180° D.No, the figure does not have rotational symmetry. A. State whether the figure has rotational symmetry. If so, state the order and magnitude of symmetry.

A.A B.B C.C D.D Example 2 A.Yes, order 8 and magnitude 45° B.Yes, order 6 and magnitude 60° C.Yes, order 4 and magnitude 90° D.No, the figure does not have rotational symmetry. B. State whether the figure has rotational symmetry. If so, state the order and magnitude of symmetry.

A.A B.B C.C D.D Example 2 A.Yes, order 3 and magnitude 90° B.Yes, order 4 and magnitude 90° C.Yes, order 2 and magnitude 180° D.No, the figure does not have rotational symmetry. C. State whether the figure has rotational symmetry. If so, state the order and magnitude of symmetry.

Concept

Example 3 Three-Dimensional Symmetry A. State whether the figure has plane symmetry, axis symmetry, both, or neither. Answer: both plane and axis symmetry

Example 3 Three-Dimensional Symmetry B. State whether the figure has plane symmetry, axis symmetry, both, or neither. Answer: neither plane nor axis symmetry

A.A B.B C.C D.D Example 3 A.plane symmetry B.axis symmetry C.both D.neither A. State whether the figure has plane symmetry, axis symmetry, both or neither.

A.A B.B C.C D.D Example 3 A.plane symmetry B.axis symmetry C.both D.neither B. State whether the figure has plane symmetry, axis symmetry, both or neither.

End of the Lesson