Unit 1, Lesson 6
No Bending or Stretching
Accelerated 7
Preparation
Lesson Narrative
In this lesson, students compare the side lengths and angle measures of a figure and its image under a translation, rotation, or reflection. They observe that the corresponding sides are the same length and the corresponding angles have the same measure, and learn that a transformation with this property is called a rigid transformation. In order to observe this property, students create a measuring tool using available materials (MP5). Then, students identify which figure is the image of an original under a rigid transformation and make arguments to explain their reasoning (MP3).
- Comprehend the phrase “rigid transformation” to refer to a transformation where all pairs of corresponding distances and corresponding angle measures in the figure and its image are the same.
- Draw and label a diagram of the image of a polygon under a rigid transformation, including calculating side lengths and angle measures.
- Identify (orally and in writing) a rigid transformation using a drawing of a figure and its image.
Let’s compare measurements before and after translations, rotations, and reflections.
- I can describe the effects of a rigid transformation on the lengths and angles in a polygon.
Required Materials
Activity 3
Required Preparation
None
corresponding
Corresponding parts are the parts that match up between a figure and its scaled copy. They have the same relative position. Points, segments, angles, or distances can be corresponding.
Point
rigid transformation
A rigid transformation is a move that does not change any measurements of a figure. Translations, rotations, and reflections are rigid transformations. So is any sequence of these.
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