Nash, Susan Lake View High School

OBJECTIVES The student will: 1. Define rotation as the composite of two reflections over intersecting lines. 2. Identify rotation images of a figure. 3. Recognize and apply the properties of rotation. EQUIPMENT AND MATERIALS Rotogram Overhead projector Markers for overhead Transparencies of figures showing reflection, translation, and rotation. RECOMMENDED STRATEGIES Demonstrate and review concept and properties of reflection and translation. a) There is a one-to-one correspondence between points in a plane and their reflection through a given line. b) Reflections of a set of points through a line preserves co- linearity, distance, and angle measure. c) Line reflection changes the orientation of a figure. d) Translation preserves orientation of a figure. Introduce rotation as a composite of two reflections across intersecting lines. Show this using transparencies, rotogram, coins, and other objects available to you. Emphasize that since rotations are composites of reflections; the properties are similar to reflections and translations. Provide additional opportunities for reinforcement of concepts using worksheets.
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