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
snoitcelfeR
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