Transformations and Congruence Flashcards

Grade 8 · Math · Flashcards

Core vocabulary for understanding geometric transformations and congruent figures.

Flashcards

Translation: A slide; moves every point the same distance and direction. Rule: (x, y) → (x+a, y+b)
Reflection over x-axis: (x, y) → (x, -y); y-coordinate changes sign
Reflection over y-axis: (x, y) → (-x, y); x-coordinate changes sign
Rotation 90° counterclockwise: (x, y) → (-y, x)
Rotation 180°: (x, y) → (-x, -y); same result clockwise or counterclockwise
Rotation 90° clockwise: (x, y) → (y, -x)
Dilation: Multiplies all distances from the center by the scale factor k
Scale factor > 1: Dilation enlarges the figure
Scale factor between 0 and 1: Dilation shrinks the figure
Rigid transformation / Isometry: Preserves side lengths and angle measures; includes translation, reflection, rotation
Congruent: Same shape and same size; symbol ≅
Similar: Same shape but different size; symbol ~
Orientation: The order (clockwise or counterclockwise) of vertices; reflections reverse it, rotations and translations do not