Unit 3 · Transformations

3.1Introduction to Transformations

Quick Answer

A transformation maps every point of a figure to a new location. The original figure is the pre-image; the result is the image. Rigid motions (isometries) preserve size and shape: translations, reflections, rotations. Non-rigid transformations (like dilations) change size.

Essential Question

What is a transformation, and what distinguishes a rigid motion from a non-rigid transformation?

Learning Goals

  • 1Define transformation, pre-image, and image.
  • 2Identify rigid motions (isometries).
  • 3Classify transformations as rigid or non-rigid.
  • 4Use prime notation to label image points.

Key Vocabulary

Transformation

A function that maps each point of a figure to a new location.

Pre-image

The original figure before a transformation.

Image

The resulting figure after a transformation.

Rigid motion (Isometry)

A transformation that preserves distance and angle measure; the image is congruent to the pre-image.

Prime notation

Using A′ (A-prime) to label the image of point A.

Full lesson content coming soon

Worked examples, guided practice problems, a workbook, quiz, and downloadable PDF resources will be added to this lesson in Phase 2. The learning goals and vocabulary above reflect the complete lesson scope.