Transformations/Rigid Motions

Opposite Isometry

preserves the size, but the order of the vertices changes

Glide Reflection

a composition of a translation and a reflection

Identity Transformation

a rotation of 360° will always map a figure back on to itself

Transformation

is a change in the position, shape, or size of a figure

Vector

is a directed line segment that has both length and direction

Rotation

is a rigid motion that turns a figure about a fixed point called the center of rotation

Rigid Motion

is a transformation that changes only the position of the figure (length and angle measures are preserved). 1. reflection 2. rotations 3. translation

Isometry

is a transformation that does not change in size. These include all of the rigid motions: reflections, translation and rotations.

Lines Of Symmetry

is equidistant from all corresponding pairs of points

Rotations Symmetry

is rotation that maps a figure back on to itself

Angel of Rotation

is the number of degrees the figure rotates. A positive angle of rotation turns the figure counterclockwise (a negative angle of rotation can be used for clockwise rotations).

Pre-image

is the original figure prior to any transformation being applied to it

Image

is the result of a transformation of a figure (called the pre-image). To identify the image of a point, use prime notation. The image of point A is A' (read as A prime).

Regular Polygons

polygons in which all sides and angles are congruent

Direct Isometry

preserves size and the other (orientation) of the vertices.

Point Symmetry

when reflecting an obect through a point, the image and pre-image creates BLANK and the object will look exactly the same upside down