Congruence Through Transformations Worksheets, Grade 8 (8.G.A.2) – Free PDF + Answer Key

First page of the congruence through transformations practice worksheet

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

Watch: Translations on the Coordinate Plane

Key idea

Congruent means a sequence of rigid motions carries one figure exactly onto the other. Orientation reversed ⇒ the sequence needs an odd number of reflections. Describe motions with their parameters, or nobody can follow them.

Sample problems

Write the definition of congruent in terms of transformations.
Reflect (1,1), (4,1), (1,3) in the y-axis. Give the new corners.
Translate your answer to item 2 by 6 right and 2 up. Give the corners.
Rotate (1,1), (4,1), (1,3) by 90° anticlockwise about the origin. Give the corners.

Common mistakes to watch for

Said no because the triangles point different ways. Orientation differing does not stop them being congruent — it only tells you the sequence needs a reflection.
Wrote “reflect it then slide it”. A reflection without its mirror line and a translation without its vector cannot be carried out, and the standard asks for a description, not a list of motion names.
Said it means they are not congruent, or that it makes no difference. Both miss that orientation is a decision procedure — it narrows the search instead of ending it.

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

How to use this set

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.