Rigid Motions Worksheets, Grade 8 (8.G.A.1) – Free PDF + Answer Key

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PDFs print on US Letter paper. Free for classroom and home use.

Key idea

Rigid motions change position only: same lengths, same angles, parallel stays parallel. Reflection reverses the corner order; rotation does not.

Name the three rigid motions and say what each one does.
Triangle with corners (1,1), (4,1), (1,3) is translated 5 right, 2 up. Give the new corners.
Measure one side of your triangle before and after that translation. What do you find?
Reflect (1,1), (4,1), (1,3) in the x-axis. Give the new corners.

Said the shape gets bigger or the angles change. Children expect a transformation to visibly DO something, so “nothing changed” feels like a wrong answer.
Said it means the shape changed, or that it was rotated. The lengths and angles are the SAME for both transformations, so nothing except orientation can separate them.
Agreed, or corrected the answer without saying why. The both-sides-turned-equally argument is the reason, and the tracing-paper check is what makes it convincing rather than asserted.

The answer key explains each one, so you can tell what a wrong answer means.

Teach with the slides (about 15 minutes), or watch the video together.
Practice with the worksheet. Questions climb from fluency to application to reasoning.
Check understanding with the exit ticket, and send the homework home.
Mark with the answer key — each answer shows the steps and the most likely mistake.