Prentice Hall Geometry

Concept Byte: Tracing Paper Transformations

Use With Lesson 9-3

ACTIVITY

In Lesson 9-1, you learned how to describe a translation using variables. In these activities, you will use tracing paper to perform translations, rotations, and reflections. You will also describe certain rotations and reflections using variables.

Activity 1

You can use the vector arrow shown in the diagram to represent the translation open x comma y close rightwards arrow . open x plus 4 comma y plus 2 close .  The translation shifts cap delta eh b c  with eh open negative 3 comma 3 close comma b open negative 1 comma 1 close comma , and c open 1 comma 4 close  to cap delta , eh prime , b prime , c prime  with eh prime , open 1 comma 5 close comma , b prime , open 3 comma 3 close , and , c prime , open 5 comma 6 close .  You can see this translation using tracing paper as follows:

A graph has triangle ABC with vertices A(negative 3, 3), B(negative 1, 1), and C(1, 4) and triangle A’B’C’ with vertices A’(0, 5), B’(3, 3), and C’(5, 6). A vector extends from the origin to (4, 2).

  • Step 1 Draw cap delta eh b c  and the vector arrow on graph paper. Also, show the line containing the arrow.
  • Step 2 Trace cap delta eh b c  and the vector arrow.
  • Step 3 Move your tracing of the vector arrow along the vector line until the tail of the tracing is on the head of the original vector arrow. The vertices of your tracing of cap delta eh b c  should now be at eh prime , open 1 comma 5 close comma , b prime , open 3 comma 3 close comma , and , c prime , open 5 comma 6 close .

    The tracing has triangle ABC over triangle A’B’C’, with the vector now from (4, 2) to (8, 4).

Use tracing paper. Find the translation image of each triangle for the given vector.

  1. A graph of triangle PQR has vertices P(1, negative 2), Q(2, 0), and R(3, negative 3), with vector from the origin to (negative 1, 3).
  2. A graph of triangle DEF has vertices D(0, 1), E(1, 3), and F(2, 0), with vector from the origin to (3, negative 2).
  3. A graph of triangle XYZ has vertices X(1, negative 2), Y(2, 0), and Z(3, negative 3), with vector from the origin to (2, 1).
  4. Show that the composition of the translation in Question 1 followed by the translation in Question 2 gives you the translation in Question 3.

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Table of Contents

Prentice Hall Geometry Chapter 1 Tools of Geometry Chapter 2 Reasoning and Proof Chapter 3 Parallel and Perpendicular Lines Chapter 4 Congruent Triangles Chapter 5 Relationships Within Triangles Chapter 6 Polygons and Quadrilaterals Chapter 7 Similarity Chapter 8 Right Triangles and Trigonometry Chapter 9 Transformations Chapter 10 Area Chapter 11 Surface Area and Volume Chapter 12 Circles Skills Handbook Reference Visual Glossary Selected Answers Index Acknowledgments