Unit 1 Transformations
Half Turn
180°
90° Turn
90°
Pre Image
A figure BEFORE a transformation is applied. The ORIGINAL figure.
Rotational Symmetry
A figure can be rotated less than 360° around a central point and coincide with the original figure.
Line of Reflection
A line that a figure is flipped across to create a mirror image of the original figure
Axis of symmetry/line of symmetry
A line that divides a plane figure or a graph into two congruent reflected halves
Basic Rigid Motion
A transformation that preserves side lengths and angle measures. Direction isn't preserved << translations, reflections, & dilations >> Also called an isometry.
Composite Transformation
A transformation that results from two or more transformations. The image of one transformation is the pre-image of the next transformation.
Translation
A transformation that shifts or slides every point of a figure or graph the same distance in the same direction. (slide)
Prime Notation
After a transformation, corresponding points are labeled using '
Isometry
Rigid transformation that preserves length and angle measures, as well as perimeter and area. Reflection, rotation, translation. NOT a dilation
Rotation of -180°
Rotate the graph 180° clockwise
Definition - Rotation of 180°
Rotate the graph 180° counter-clockwise. Note - rotating a graph 180° clockwise happens to be the same thing
Definition - Rotation of 270°
Rotate the graph 270° counter-clockwise
Definition - Rotation of 90°
Rotate the graph 90° clockwise
Definition - Rotation of 90°
Rotate the graph 90° counter-clockwise
Image
The figure you get AFTER a transformation is applied.
Rotation
The transformation of a figure that is around a fixed point. (turn)
Reflection- Definition
The transformation of a figure that is over a line (flip).
Line of Symmetry
a line that divides a figure into two halves that are mirror images of each other
Dilation- Definition
a transformation that enlarges or reduces the original figure proportionally by multipling both coordinates by the scale factor. (enlarge or reduce)
Rule - Reflection over the y axis
change the sign of the x coordinate.
Rule - Reflection over the x axis
change the sign of the y coordinate.
x-axis
horizontal axis (left and right)
Counterclockwise
in the direction that is opposite of the direction the hands on the clock move
Clockwise
in the same direction as the rotating hands of a clock
Rule - Reflection over y=-x
switch the x and y coordinates and negate them. (Change both signs)
Rule - Reflection over the line y=x
switch the x and y coordinates.
Angle of rotation
the angle through which a preimage is rotated to form the image; the number of degrees a figure is rotated
y-axis
vertical axis (up and down)