Things Needed Today (TNT): Topic: Congruency & Review of Rotations Math CC7/8 – May 22 Things Needed Today (TNT): Pencil/Math Notebook Transformation Brochure Math Notebook: Topic: Congruency & Review of Rotations HW: Transformation WS

What’s Happening Today? Congruency Review of Rotations

Notes When making transformations of figures, you need to pay attention to two important things: _______________ and _______________ . Distance Angle

Reflection: Maintain a 90 degree angle with perpendicular bisector Original point and image must be SAME distance from line of reflection Rotation: Mark CENTER of rotation Measure distance of each point from center of rotation Rotate each point the same angle Translation: Measure distance of slide Keep parallel lines of slide

Are the rules the same for rotations for clockwise & counterclockwise? When a point (x, y) is rotated counterclockwise about the origin, the following rules are true: rotation of 900 (x,y) (-y, x).  rotation of 1800 (x,y) (-x, -y). rotation of 2700 (x, y) (y, -x). When a point (x, y) is rotated clockwise about the origin, the following rules are true: rotation of 900 (x,y) (y, -x).  rotation of 1800  same as counterclockwise. Since it is a half-turn, the image is the same no matter the direction! rotation of 2700 (x, y) (-y, x). .

Connecting Congruent Polygons

Objects are congruent if they are exactly the same shape and size.

Are these shapes congruent?

Similar objects are the same shape but are not the same size.

Are these shapes similar?

Matching parts of congruent or similar figures. Corresponding Parts Matching parts of congruent or similar figures.

What parts are corresponding? B E F C D G H B X Y Z A C

Transformations Translation Reflection Rotation Dilation

Translation (Slide) A figure moves along a straight line. Figure 1

A mirror image is created across a line. Reflection (Flip) A mirror image is created across a line. Figure 1 Figure 2 Figure 1 Figure 2

A figure turns around a point. Rotation (Turn) A figure turns around a point. 90° 90° 180° 180° Figure 2 Figure 1 Figure 1 Figure 2 Figure 2 Figure 2

Name the Transformation Rotation clockwise 90° 1 1 Translation 2 2 1 1 2 2 Rotation Reflection 180°