8-10 Transformations

Warm UpWarm Up

Lesson PresentationLesson Presentation

Problem of the DayProblem of the Day

Lesson QuizzesLesson Quizzes

8-10 Transformations

Warm UpFind the supplement of each angle.

1. 35°

2. 95°

145°

85°

8-10 Transformations

Problem of the Day

Imagine that each figure is folded so that point A lies on point B. What figures would be formed?

trapezoid, right triangle

8-10 Transformations

Learn to use translations, reflections, and rotations to transform geometric shapes.

8-10 Transformations

Vocabulary

transformationtranslationrotationreflectionline of reflection

8-10 Transformations

A rigid transformation moves a figure without changing its size or shape. So the original figure and the transformed figure are always congruent.

A translation is the movement of a figure along a straight line.

A rotation is the movement of a figure around a point. A point of rotation can be on or outside a figure.

When a figure flips over a line, creating a mirror image, it is called a reflection. The line the figure is flipped over is called line of reflection.

8-10 Transformations

Additional Example 1A: Identifying Transformations

Tell whether each is a translation, rotation, or reflection.

The figure is flipped over a line.

It is a reflection.

8-10 Transformations

Additional Example 1B: Identifying Transformations

Tell whether each is a translation, rotation, or reflection.

The figure is moved along a line.

It is a translation.

8-10 Transformations

Additional Example 1C: Identifying Transformations

Tell whether each is a translation, rotation, or reflection.

The figure moves around a point.

It is a rotation.

8-10 Transformations

Check It Out: Example 1A

Tell whether each is a translation, rotation, or reflection.

The figure is flipped over a line.

It is a reflection.

8-10 Transformations

Check It Out: Example 1B

Tell whether each is a translation, rotation, or reflection.

The figure moves around a point.

It is a rotation.

8-10 Transformations

Check It Out: Example 1C

Tell whether each is a translation, rotation, or reflection.

The figure is moved along a line.

It is a translation.

8-10 Transformations

A full turn is a 360°

rotation. So a turn

is 90°, and a turn

is 180°.

12__

14__

90°

180°

360°

8-10 Transformations

Additional Example 2A: Drawing Transformations

Draw each transformation.

Draw a 180° rotation about the point shown.

Trace the figure and the point of rotation.

Place your pencil on the point of rotation.

Rotate the figure 180°.

Trace the figure in its new location.

8-10 Transformations

Additional Example 2B: Drawing Transformations

Draw each transformation.

Draw a horizontal reflection.

Trace the figure and the line of reflection.

Fold along the line of reflection.

Trace the figure in its new location.

8-10 Transformations

Check It Out: Example 2A

Draw each transformation.

Draw a 180° rotation about the point shown.

Trace the figure and the point of rotation.

Place your pencil on the point of rotation.

Rotate the figure 180°.

Trace the figure in its new location.

8-10 Transformations

Check It Out: Example 2B

Draw each transformation.

Draw a horizontal reflection.

Trace the figure and the line of reflection.

Fold along the line of reflection.

Trace the figure in its new location.

8-10 Transformations

Standard Lesson Quiz

Lesson Quizzes

Lesson Quiz for Student Response Systems

8-10 Transformations

Lesson Quiz

1. Tell whether the figure is translated, rotated, or

reflected.

2. Draw a vertical reflection of the first figure in

problem 1.

rotated

8-10 Transformations

1. Identify the transformation of the figure.

A. translation B. reflection C. rotation D. none

Lesson Quiz for Student Response Systems

8-10 Transformations

2. Identify the horizontal reflection of the figure.

A. B.

C. D.

Lesson Quiz for Student Response Systems