Geometric transformations and congruence

Part 1

I explain the basics of these congruent transformations: translation, rotation, and reflection. A rotation always happens around some point (a center point). A reflection always happens across (or in) some particular line. I also show how to use transparent paper to rotate a triangle around a point.

Part 2

We look at a few simple exercises that are based on the fact that the basic geometric transformations (translations, reflections, rotations) preserve angles, distances, and parallel lines. In other words, the image of a figure under these transformations is congruent to the original.

See also

Translations in the coordinate grid — video lesson

Math Mammoth Grade 8 curriculum

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