In this unit, students explore the rigid transformations (translations, rotations, and dilations) and conclude that there are aspects of shapes that stay the same. Students begin to formalize terminology for geometric figures and transformations for them.
When figures are transformed some attributes change and others stay the same. Students will investigate lengths and angles and the results of transformations on lengths and angles. They also explore the results of rotations, reflections, and translations on parallel lines.
Key Concepts:
 Some attributes of geometric figures are unchanged when the figure undergoes a reflection, rotation, or translation.
 Figures that have measures (length of segments, angle measures) are taken to congruent figures when they are transformed through a reflection, rotation, or translation.
 Parallel lines are taken to parallel lines when rotated, reflected, or translated because the distance between the lines is maintained.
Prior Knowledge Needed:
 Draw points, lines, line segments, rays, angles, and perpendicular and parallel lines; (Grade 4, Unit 13; 4.G.A.1)
 Recognize a line of symmetry for a twodimensional figure; (Grade 4, Unit 13; 4.G.A.3)
Units on the Horizon:
 Understanding congruence through transformations (Grade 8, Unit 2)
 Understanding similarity (Grade 8, Unit 3)
Lessons

Lesson objective: Understand that the three rigid transformations are rotations, reflections, and translations, and that each one produces an image congruent to the original. Students bring prior knowledge of congruency as "same size, same shape." This ...

Lesson objective: Fluently identify the rigid transformations. This lesson helps to build fluency with identifying rigid transformations. This work develops students' understanding that the three rigid transformations are rotations, reflections, and tra...

Lesson objective: Describe rotations and reflections. This lesson helps to build fluency with describing rotations and reflections. Rotations and reflections are used here because they give students an opportunity to work with clockwise and counterclock...

Lesson objective: Apply knowledge of transformations to describe the movements of a game piece. This lesson provides an opportunity for students to apply their knowledge and understanding of rigid transformations to a reallife situation. Students are a...

Lesson objective: Understand that side lengths and angle measurements remain unchanged when a figure undergoes a rigid transformation. Students bring prior knowledge of rigid transformations. This prior knowledge is extended to describing congruence as ...

Lesson objective: Fluently name corresponding sides and angles on images that have been transformed. This lesson helps to build fluency with naming corresponding sides and angles. This work develops students' understanding that figures that have measure...

Lesson objective: Determine whether or not a transformation took place. This lesson helps to build procedural skill with determining whether or not a transformation took place. Students learn to recognize that in order for a transformation to have taken...

Lesson objective: Apply rigid transformations to several objects to plan rearranging a room. This lesson provides an opportunity for students to apply their knowledge and understanding of rotations, reflections, and translations to a reallife situation...

Lesson objective: Determine what happens to parallel sides when a figure undergoes a rigid transformation. Students bring prior knowledge of parallel lines from 4.G.A.1, and transformations from 8.G.A.1.a. This prior knowledge is extended to bridge a re...

Lesson objective: Solve problems using knowledge of rigid transformations. This lesson provides an opportunity for students to apply their knowledge and understanding of the connection between parallel lines and rigid transformations to a reallife situ...