Transformations and Symmetry Section 7-1 Transformations and Symmetry

By moving all the points of a geometric figure according to certain rules, you can create an image of the original figure. This process is called transformation. If the image is congruent, the process is called a rigid transformation.

If size and shape are not preserved, it is called a non-rigid transformation.

Translation is the simplest type of isometry. Trace a figure onto patty paper and slide it along a straight path without turning. Notice all points move the same distance along parallel paths to form its image. A translation also has a particular direction called the translations vector. Translation Vector

Center of Rotation Rotation is another type of isometry. In a rotation, all the points in the original figure rotate or turn an identical number of degrees. You can define a rotation by its center point, the number of degrees, and the direction.

Reflection is a type of isometry that produces a figure’s mirror image Reflection is a type of isometry that produces a figure’s mirror image. If you draw a figure onto a piece of paper, place the edge of a mirror perpendicular to your paper and look at the figure in the mirror, you will see the reflected image of the figure. The line where the mirror is placed is called the line of reflection. Reflection is a type of isometry that produces a figure’s mirror image. If you draw a figure onto a piece of paper, place the edge of a mirror perpendicular to your paper and look at the figure in the mirror, you will see the reflected image of the figure. The line where the mirror is placed is called the line of reflection. Mirror

The Basic Property of a Reflection