9-3: Rotations

Key Concept

A rotation is a rigid motion that turns a figure about a fixed point called the center of rotation. The angle of rotation is the number of degrees the figure rotates. A positive angle of rotation turns the figure counterclockwise.

A graph of a parallelogram with vertices (0, 0), (1, 2), (3, 2), and (2, 0). A positive angle of rotation of 360° about (0, 0) moves the parallelogram back to the same location.

Part 1

Example Recognizing Rotations

Identify which transformation is a rotation.

First transformation.

Second transformation.

Third transformation.

Solution

The first transformation is a rotation about the origin.

The origin is the center of rotation, moving vertex B(2, 1) to vertex B´(1, −2).


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Table of Contents

Digits, Grade 8, Volume 2, Homework Helper Unit D: Two-Dimensional Shapes Unit E: Measurement and Data Unit F: Personal Financial Literacy Unit G: Step-Up Lessons English/Spanish Glossary Formulas Math Symbols Formulas Measures Properties