Transformations: Rotations, Reflections, Translations

Advanced Transformations - Reflections

Students should be able to:

Predict and describe positions and orientations of two-dimensional shapes after transformations such as reflections, rotations, and translations.

Definition

The word transform means "to change." In geometry, a transformation changes the position of a shape on a coordinate plane. What that really means is that a shape is moving from one place to another. There are three basic transformations:

Flip (Reflection)
Slide (Translation)
Turn (Rotation)

Being able to visualize the movement of a shape is very important. The SMARTBoard mini-movies below show a letter, or a polygon (after all, block letters are really just polygons), in their original positions before being transformed. By clicking the play button, we are able to watch the path the letter takes while being transformed and see their ending positions after the slide, flip, or turn has taken place.

Flip (Reflection)

A FLIP takes place when a shape is flipped across a line and faces the opposite direction. Because the shape ends up facing the opposite direction, it appears to be reflected, as in a mirror. Hence the name REFLECTION. A shape can reflect across the vertical axis, or y-axis, or it can reflect across the horizontal axis, or x-axis.

Practice

You can make your own reflections using the Alphabet Symmetry Tool. Drag a letter to the workspace and use the tools to the right to reflect it, rotate it, duplicate it, and more.