Here are some animations I did to help some concepts, particularly in geometry, “come alive”. The bulleted links will take you to the youtube videos. If you’d like to use the PowerPoint I used for the video—maybe so you can turn off the timings, modify it as necessary, and drive it yourself with your own students—you can download the pptx file by clicking in the bracketed link to the right.

**Basic Rigid Motions (Basic Isometries)**

- Composition of Rigid Motions (translation, rotation, and reflection)
*[pptx]* - Angle-Side-Angle Congruence by Basic Rigid Motions
*[pptx]* - Side-Angle-Side Congruence by Basic Rigid Motions
*[pptx]*

**Pythagorean Theorem**

- Root Spiral of Theodorus
*[pptx]* - Constructing Square Roots on the Number Line
*[pptx]* - Pythagorean Theorem proof from similar right triangles
*[pptx]*

**Show Your Work (solving for x)**

This is an old PowerPoint I made years ago trying to get across this crucial habit to my students so we—they and I—could see what they were doing. I ought to slick it up a bit, but I think it still has some validity. I turned the PowerPoint into a video, titled—surprise!—”Show Your Work” about 5 years ago.