Preserving Parallelism-Reflection

For Math 2 MVP Module 3 Lesson 4

Follow the steps below to construct the task: Step 1: Using the polygon tool, create any polygon on the plane. Pay attention to the labels and the line segments of your polygon. Step 2: Reflect your polygon across the given line. Make a note of corresponding line segments in the pre-image and image. Step 3: Measure the slope of each line segment.

Were any of your corresponding line segments parallel to one another? If so, why are some parallel to each other and not others? If not, why not?

Repeat the steps from the first applet with one exception. When constructing your polygon, use the given line segment as one side of your polygon.

Did you have any corresponding lines that were parallel after the reflection? Which ones? Why did they end up parallel? Use your findings to complete this sentence: After a reflection corresponding line segments in an image are [always, sometimes, never] parallel.