RIGID MOTION IN A PLANEChapter 7.1

New Vocabulary…

Pre Image – The original figure in the transformation of a figure in a plane.

Image – The new figure that results from the transformation of a figure in a plane.

New Vocabulary…

Transformation – The operation that maps, or moves, a pre image onto an image. 3 basic transformations are reflections,

rotations, and translations.

http://www.youtube.com/watch?v=Np6Qm9sQV68&feature=youtu.be

TRANSFORMATIONSHUFFLE

Example…

Mapping: A way to describe a transformation. ABC is mapped on DEF ABC DEF

Isometry: A transformation that preserves lengths. Also called a Rigid Transformation.

REFLECTIONSChapter 7.2

New Vocabulary… Reflection – A type of transformation that

uses a line that acts like a mirror, called a line of reflection, with an image reflected in the line.

Line m is the Line of Reflection. Reflections are a type of Isometry.

m

Reflections… Rules

If P is not on line m, then m is the perpendicular bisector of PP’.

If P is on m, then P = P’.m m

P’PP’

P

Reflections… Rules Continued If (x, y) is reflected in the x-axis, its

image is the point (x, -y). If (x, y) is reflected in the y-axis, its

image is the point (-x, y).Reflect the GREEN dot over the y-axis. What are the coordinates of the pre image and image???

Reflect the PINK dot over the x-axis. What are the coordinates of the pre image and image???

Line of Symmetry…