Wyoming Math 8.G.2

Math8th GradeGeometry

The Standard

Recognize through visual comparison that a two-dimensional figure is congruent to another if the second can be obtained from the first by a sequence of rotations, reflections, and translations; given two congruent figures, describe a sequence that exhibits the congruence between them.

2023 Wyoming Mathematics Content and Performance Standards · Understand congruence and similarity using physical models, transparencies, or geometry software.

Teacher's field guide

What This Standard Means

What Students Need to Do: Students compare flat figures, then check whether a slide, turn, flip, or combination makes them overlap exactly. They describe the moves in order.
What Mastery Looks Like: A student can line up every corner, not just one edge. They can describe each move precisely, giving the distance and direction, rotation center and angle, or reflection line.
Common Misconceptions: Students may call figures congruent because they have equal area, even when their shapes differ. They may treat a mirror image as a rotation or think turning a figure changes its shape.
How to Assess It: Exit ticket: Triangle A(0,0), B(2,0), C(0,1) maps to A′(4,2), B′(2,2), C′(4,3). Name a sequence of moves and show where each vertex lands.

Lesson moves

Ways to Teach It

Trace an L-shaped polygon on acetate, then slide, turn, and flip it to cover matching outlines on grid paper.
Show a block letter F and its mirror image; ask, 'Can slides and turns match them, or must you flip one?'
Give partners cards showing congruent triangles on grids; have them write move sequences, swap cards, and check where each vertex lands.
Show a photo of a floor tile pattern; have students trace one tile and mark moves that place it on two others.

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