ROTATIONS

Nash, Susan                     Lake View High School
                                1-312-880-8140
                              

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.