geometry transformation definitions

reflection

(flip) an isometry in which a figure and its image have opposite orientations

translation

(slide) an isometry that maps all points of a figure the same distance in the same direction. use vectors

point symmetry

180° rotational symmetry

rotation

A composition of reflections in two intersecting lines is a ________

translation

A composition of reflections in two parallel lines is a ________

reflections

In a plane, one of two congruent figures can be mapped onto the other by a composition of at most three ________

reflectional symmetry or line symmetry

One half of the figure is a mirror image of its other half

transformation

a change in its position, shape, or size

dilation

a change in size of an image making the 2 figures similar

composition

a combination of two or more transformations

reduction

a dilation with a scale factor between 1 and 0

enlargement

a dilation with a scale factor greater than 1

isometry

a transformation in which the preimage and image are congruent

reflections

a translation or rotation is a composition of 2 ______

symmetry

an isometry that maps the figure onto itself

glide reflection

composition of a glide (translation) and a reflection in a line parallel to the glide vector

rotation

need to know the center of rotation (a point), the angle of rotation (a positive number of degrees), and whether the rotation is clockwise or counterclockwise

rotational symmetry

symmetry where a figure its own image for some rotation of 180° or less

scalar multiplication

the multiplication of each entry in a matrix by the same number, the scalar

preimage

the original figure

image

the resulting image