School Improvement in Maryland

Lesson Plan: Lesson plans were written by Maryland mathematics educators and could be used when teaching the concepts.

Goal 2 Geometry, Measurement, And Reasoning

Expectation 2.1 The student will represent and analyze two- and three-dimensional figures using tools and technology when appropriate.

Indicator 2.1.3 The student will use transformations to move figures, create designs, and/or demonstrate geometric properties.

Lesson Content

Reflections over Two Lines and Dilations

Objective

Students will be able to identify and compare the three congruence transformations, apply the three congruence transformations to coordinates of the vertices of figures, identify and apply dilations, and apply transformations to real-world situations.

Approximate Time

45-minute lesson

Materials Needed

Lesson Structure

    Essential Questions

    What are the similarities and differences between the images and pre-images generated by each of the rigid transformations?
     
    What is the relationship between the coordinates of the vertices of a figure and the coordinates of the vertices of the figure's image generated by each of the rigid transformations?
     
    How can transformations be applied to real-world situations?

    Warm-Up/Opening Activity

    Investigate reflections over parallel and intersecting lines.
     
    Worksheet: Reflections over Two Lines

    Development of Ideas

    Activity: Investigate dilations using measurement.
     
    Worksheet: Dilations using Measurement

    Closure

    Summarize transformations using the worksheet Transformations

Additional Resources

National Council of Teachers of Mathematics (NCTM). Navigating Through Geometry in Grades 6-8, 2002, Chapter 3 - Transformations and Symmetry, pp. 43-58.
 
National Council of Teachers of Mathematics (NCTM). Navigating Through Geometry in Grades 9-12, 2001, Chapter 1 - Transforming Our World, pp. 9-26.
 
Dixon, Juli, Movements in the Plane: Conjecturing about Properties of Transformations, NCTM Math On-Line January 2003
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