Math CC7/8 – May 22
Things Needed Today (TNT):
Pencil/Math Notebook
Transformation Brochure
Math Notebook:
1.Topic: Congruency & Review of Rotations
2.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:
Distance
_______________ and
_______________
.
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 halfturn, the image is the same no matter the direction!
rotation of 2700 (x, y)
(-y, x).
Connecting Congruent Polygons
Congruent
Objects are congruent if they are
exactly the same shape and size.
Are these shapes congruent?
Similar
Similar objects are the same shape
but are not the same size.
Are these shapes similar?
Corresponding Parts
Matching parts of congruent
or similar figures.
What parts are
corresponding?
A
B
C
D
E
F
G
H
B
X
Y
Z
A
C
Transformations
Translation
Reflection
Rotation
Dilation
Translation
(Slide)
A figure moves along a straight line.
Figure 1
Figure 2
Figure 1
Figure 2
Reflection
(Flip)
A mirror image is created across a line.
Figure 1
Figure 2
Figure 1
Figure 2
Rotation
(Turn)
A figure turns around a point.
90°
180°
90°
180° Figure 2
Figure 1
Figure 1
Figure 2
Figure 2
Figure 2
Name the Transformation
1
Rotation
90°
clockwise
1
Translation
2
2
1
1
Rotation
180°
2
2
Reflection