Line Symmetry
a line that divides a figure into two halves that are mirror images of each other
Line of Symmetry
A line that divides a figure into two congruent halves that are mirror images of each other.
Enlargement
a dilation with a scale factor greater than 1
Reduction
a dilation with a scale factor less than 1.
Reflection
a transformation that "flips" a figure over a mirror or reflection line.
Rotation
circular movement around an axis
Rotational Symmetry
the ability of a figure to be rotated less than a full circle and exactly match its original image
Scale factor
the ratio of the lengths of two corresponding sides of two similar polygons
Similar figures
have the same shape but not necessarily the same size
Similarity transformation
a dilation or a composition of rigid motions and dilations
Transformation
a process which changes the position (size or orientation as well) of a shape
Translation
a geometric transformation that moves every point of a shape by the same distance in a given direction
Vector
a quantity that has magnitude and direction
Corresponding parts of similar triangles
Two triangles are similar if and only if the corresponding sides are in proportion and the corresponding angles are congruent. There are three accepted methods of proving triangles similar: AA, SAS, and SSS.