Lines are taken to lines, and line segments to line segments of the same length

What you'll learn

1. Demonstrate experimentally that the image of a straight line under any rigid motion (translation, reflection, or rotation) is still a straight line — never a curve
2. Verify by measurement that a line segment and its image under any rigid motion have the same length
3. Explain in their own words why rigid motions are called "distance-preserving" transformations, connecting the length-preservation property to the definition of rigid motion
4. Distinguish rigid motions from non-rigid transformations (such as dilation) by identifying whether length is preserved, using measurement or coordinate calculations
5. Apply the line-preservation and length-preservation properties to predict and verify the images of line segments and lines under specific translations, reflections, and rotations

Prerequisites

• Verify experimentally the properties of rotations, reflections, and translations