A change in the orientation, size, or shape of a figure is called a transformation. You will begin to investigate symmetry and how it relates to transformations. Through this learning process, you will demonstrate how to determine if a figure has point symmetry, line symmetry, both, or neither.

Essential Question

• How can you determine if a figure has point symmetry, line symmetry, both, or neither?

 

Warm-Up

In the real world, items that can be split down the middle are referred to as symmetric. Take for example the one-dollar bill. It may look symmetric at first glance, but with careful study you can see that it is actually not symmetric. There is no way to fold a dollar bill so that each of the images on the bill match up perfectly to a corresponding image on the other side. For example, on the right hand side there is a green seal that says, "The Department of the Treasury." However, the left side of the dollar bill does not have a green seal in the corresponding position. In what other ways is the dollar bill not symmetrical? Now you will continue your investigation of symmetry and how it relates to geometric figures on the coordinate plane.