9-2: Reflections

Key Concept

A reflection, or flip, is a rigid motion that flips a figure over a line called the line of reflection.

If a point A is on the line of reflection, then its image A′] is itself (A′=A).

If a point B is not on the line of reflection, then B and B′ are on opposite sides of the line of reflection. They are on a line perpendicular to the line of reflection, and are the same distance from the line of reflection.

B(−3, 2) and B´(3, 2) are the same distance, 3 units, from the line of reflection, the y-axis.

Part 1

Example Recognizing Reflections

Determine which transformation is a reflection.

First transformation.

Second transformation.

Third transformation.

Solution

The second transformation is a reflection across the y-axis.

Solution explanation.


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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