Rotation
Turn
Reflection
Flip or mirror image
Translation
slide
Dilation
enlarge or reduce a shape by multiplying/dividing by a scale factor
Congruent
shapes that are exactly the same—same shape and same size
Similar
shapes that have the same shape but different (proportional) size
Reflection across the x-axis
Keep x-value the same, take the opposite of new y-value [Example: (3, 2) (3, -2)]
Reflection across the y-axis
Keep y-value the same, take opposite of new x-value [Example: (3, 2) (-3, 2)]
Rotation 90o clockwise
Switch coordinates, take opposite of new y-value [Example: (3, 2) (2, -3)]
Rotation 90o counterclockwise
Switch coordinates, take opposite of new x-value [Example: (3, 2) (-2, 3)]
Rotation 180
Take opposite of both x-value and y-value [Example: (3, 2) (-3, -2)]
Translations
: If given a rule, use the coordinates given and “plug” them in for the x and y in the second part of the rule [Example: Rule: (x, y) (x – 10, y + 4), Coordinate given: (3, 2); (3 – 10, 2 + 4) = (-7, 6)] -If given “directions”, remember “left” and “right” affect the x-value. “Up” and “Down” affect the y-value
Dilations
multiply both the x and y values by the scale factor (k) given. [Example: k = 3, coordinate given (3, 2) (9, 6) or k = ½ , coordinate given (3, 2) (1.5, 1)]
≅
means congruent
~
means similar
m∠x
means “ measure of angle the x
𝑿𝒀̅̅̅̅
means “line segment” or “side length” from point X to point Y
∥
means “is parallel to”