This Instructional Activity is a part of the Lesson 7, Unit 8, Grade 8. In this activity, students explore a transformations-based proof of the Pythagorean Theorem, calling back to their work with transformations earlier in the year. Since this proof is not one students are expected to derive on their own, the focus of this activity is on understanding the steps and why they are possible from a transformations perspective. Listen for students using precise language when describing their transformations. The digital activity demonstrates the same proof in a slightly different way. Students have the opportunity to explore three different right triangles in the applets.