9 Chapter Review

Connecting BIG ideas and Answering the Essential Questions

1 Transformations When you translate, reflect, or rotate a geometric figure, its size and shape stay the same. When you dilate a geometric figure, the figure is enlarged or reduced.	Transformations (Lessons 9-1, 9-2, 9-3, and 9-5) The black triangle is the preimage of each transformation. Image Long Description	Composing Transformations (Lesson 9-6) A glide reflection moves the black triangle down 3 units and then reflects it across the line x = − 2 . x equals . negative 2 . Image Long Description Tessellations (Lesson 9-7) A tessellation uses transformations of a figure to make a repeating pattern that fills a plane. Every tessellation has at least one type of symmetry.
2 Coordinate Geometry You can show a transformation in the coordinate plane by graphing a figure and its image.
3 Visualization Visualize a transformation that maps a figure onto itself.	Symmetry (Lesson 9-4) Line Symmetry Rotational Symmetry

Chapter Vocabulary

• center of a regular polygon (p. 560)
• composition of transformations (p. 547)
• dilation (p. 575)
• glide reflection (p. 587)
• glide reflectional symmetry (p. 597)
• image (p. 544)
• isometry (p. 544)
• line symmetry (p. 568)
• preimage (p. 544)
• reflection (p. 553)
• rotation (p. 559)
• rotational symmetry (p. 568)
• tessellation (p. 595)
• transformation (p. 544)
• translation (p. 546)
• translational symmetry (p. 597)

Choose the correct term to complete each sentence.

1. A(n) ? _ modified question mark with under bar below  is a change in the position, shape, or size of a figure.
2. A(n) ? _ modified question mark with under bar below  is a transformation in which the preimage and the image are congruent.
3. In a(n) ? _ , modified question mark with under bar below , comma  all points of a figure move the same distance in the same direction.
4. A(n) ? _ modified question mark with under bar below  is a translation followed by a reflection across a line parallel to the direction of the translation.

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