Geometry: Unit 4

Math Vocab Practice

vector

a quantity that has both direction and magnitude, and is represented in the coordinate plane by an arrow drawn from one point to another

translation

a transformation that moves every point of a figure the same distance in the same direction

vertical component

the vertical change from the starting point of a vector to the ending point

transformation

a function that moves or changes a figure in some way to produce a new figure

terminal point

the ending point of a vector

similarity transformation

a dilation or a composition of rigid motions and dilations

similar figures

geometric figures that can be mapped to one another by a similarity transformation

center of rotation

the fixed point in a rotation

center of symmetry

the center of rotation in a figure that has rotational symmetry

angle of rotation

the angle that is formed by rays drawn from the center of rotation to a point and its image

center of dilation

the fixed point in a dilation

component form

a form of a vector that combines the horizontal and vertical components

composition of transformations

the combination of two or more transformations to form a single transformation

congruence transformation

also known as rigid motion, it is a transformation that preserves length and angle measure

congruent figures

geometric figures that can be mapped to one another by a rigid motion or a composition of rigid motion

reduction

a dilation in which the scale factor is greater that 0 and less than 1

line of symmetry

a line of reflection that maps a figure onto itself

rigid motion

transformation that preserves length and angle measure

rotational symmetry

a figure has rotational symmetry when the figure can be mapped onto itself by a rotation of 180^o or less about the center of the figure

preimage

the original figure before a transformation

reflection

a transformation that uses a line like a mirror to reflect a figure

rotation

a transformation in which a figure is turned about a fixed point

scale factor

the ratio of the lengths of the corresponding sides of the image and the preimage of a dilation

initial point

the starting point of a vector

image

a figure that results from the transformation of a geometric figure

line symmetry

a figure in the plane has line symmetry when the figure can be mapped onto itself by a reflection in a line

line of reflection

a line that acts as a mirror for a reflection

horizontal component

the horizontal change from the starting point of a vector to the ending point

glide reflection

a transformation involving a translation followed by a reflection

enlargement

a dilation in which the scale factor is greater than 1

dilation

a transformation in which a figure is enlarged or reduced with respect to a fixed point