Preserving Parallelism-Rotations

For Math 2 MVP Module 3 Lesson 4

Follow the steps below to construct this task. 1) Create a polygon with any number of vertices. 2) Use the point tool to place a point anywhere on the graph, outside of your polygon. 3) Select the "rotate about point tool", select your polygon, then select the point from step 2, then for the angle of rotation type the letter 'r' to attach this rotation to the slider. 4) Use the tools at your disposal to identify corresponding line segments in the pre-image and image and to make observations about their behavior. (Tip: Make corresponding segments a matching color by clicking on the segment editing color in top right edit bar.) (Tip: We are trying to make a conjecture about parallelism, what tools are at your disposal that could help determine parallelism)


After your construction and exploration of rotating polygons, choose which word best completes the statement: After a rotation, corresponding line segments in an image and its pre-image are [never, sometimes, always] parallel. Give reasons for your answer. If you choose "sometimes," be very clear in your explanation how to tell when the corresponding line segments before and after the rotation are parallel and when they are not.