This document discusses different types of congruence transformations: translations, reflections, and rotations. It provides coordinate notation to describe each transformation. Translations move a figure the same distance in the same direction and are written as (x+a, y+b). Reflections create a mirror image, with reflections across the x-axis written as (x, -y) and across the y-axis as (-x, y). Rotations turn a figure around a center point, with clockwise and counterclockwise rotations shown. The document concludes by assigning homework problems from the text.

1. 4.8 Congruence Transformations October 25, 2012
Bellwork
Find the value of x.
x = 8 x = 3
3. If the measure of vertex angle of an isosceles triangle is 112°,
what are the measures of the base angles?
34
Oct 29­2:05 PM
HW pg. 276 #4­22 evens, 26­28 1

2. 4.8 Congruence Transformations October 25, 2012
4.8 Congruence Transformations
Transformation: operation that moves or changes a figure
Image: the new figure
Translation: moves figure the same distance in same direction
Translation: slides
Reflection: creates a mirror image of original figure
:noitcelfeR
reflects
Rotation: turns a figure around the center of rotation (fixed point)
Rotation:
rotates
Oct 29­7:25 AM
HW pg. 276 #4­22 evens, 26­28 2

3. 4.8 Congruence Transformations October 25, 2012
Coordinate Notation for Translations
Translations
Original Image
(x,y) (x+a, y+b)
Oct 29­9:16 AM
HW pg. 276 #4­22 evens, 26­28 3

4. 4.8 Congruence Transformations October 25, 2012
Coordinate Notation of Reflections
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Around the x-axis Around the y-axis
Original Image Original Image
(x, y) (x, -y) (x, y) (-x, y)
Nov 1­10:43 AM
HW pg. 276 #4­22 evens, 26­28 4

5. 4.8 Congruence Transformations October 25, 2012
Coordinate Notation for a Rotation
Rotation
Angle of Rotation: rays drawn
from center of rotation to figures
Clockwise Counterclockwise
90 60
Nov 1­10:50 AM
HW pg. 276 #4­22 evens, 26­28 5

6. 4.8 Congruence Transformations October 25, 2012
Nov 1­1:01 PM
HW pg. 276 #4­22 evens, 26­28 6

7. 4.8 Congruence Transformations October 25, 2012
HW pg.276 4-22 evens, 26-28
Nov 1­1:03 PM
HW pg. 276 #4­22 evens, 26­28 7