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Learning Goal

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Describe the effect of dilations, translations, rotations, and reflections on two-dimensional figures using coordinates

Start lessonBegins with Coordinate rules rigid motions · Slides

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8.G.A.3

**8.G.A.3**: Describe the effect of dilations, translations, rotations, and reflections on two-dimensional figures using coordinates.

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8.G.A.3: Describe the effect of dilations, translations, rotations, and reflections on two-dimensional figures using coordinates.

What you'll learn

  1. Apply the coordinate rules for translations, reflections (across the x-axis and y-axis), rotations (90 degrees, 180 degrees, 270 degrees about the origin), and dilations (centered at the origin) to compute the image of a given point or set of vertices
  2. Describe the effect of each transformation on the coordinates of a figure using precise coordinate notation -- for example, "a reflection across the y-axis maps (x, y) to (-x, y)"
  3. Classify a transformation as rigid (translation, reflection, rotation) or non-rigid (dilation) and explain how the coordinate rules reveal whether side lengths are preserved or changed
  4. Determine the image of a two-dimensional figure (triangle, rectangle, or other polygon) under a single transformation by applying the coordinate rule to every vertex, then plotting the image on the coordinate plane
  5. Compare the pre-image and image of a figure under dilation with the pre-image and image under a rigid motion, articulating that dilation changes the size but preserves the shape, while rigid motions preserve both

Slides

Step through the lesson, or watch it as a narrated video • 2 slide decks

1

Coordinate rules rigid motions

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2

Dilation and comparing transformations

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Practice

Try it on your own • 2 practice sets

3

Drill

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4

Exercise

Practice problems, checked as you go

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