9.2 reflectionsimages.pcmac.org/sisfiles/schools/al/hoovercity... · 9.2 reflections determine the...
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9.2 Reflections
reflection:
propertıes:
notatıon:
a type of transfromation that maps/moves every part of
a figure over a given line
the line is called the line of reflection
(flip)
1) the preimage and image are always equidistant
from the line of reflection
2) if a point is on the line of reflection, then its image
is itself
R(line)reflection
line: will either be x = a # or y = a #
Ex: x = 4, or y = 1
**when the line is x = a # the line is vertical
**when y = a # the line is horizontal
9.2 ReflectionsFinding the Image of a ReflectionWhat are the coordinates of point P after the Ry = 1 ? Graph the point.
P
STEPS:1) determine the line of reflection
Ry = 1, line of reflection is y = 1
line of reflection, y = 1
2) COUNT how far the point is from the line of reflection
P is 3 units away from y = 1
3) P' must be the same distance on the other side of the line
Count 3 more units on the other side of y = 1
ANSWER: P' (4, 2)
9.2 ReflectionsFinding the Image of a ReflectionGraph the reflection of ABC after Ry axis.
A
B
C
STEPS:1) Determine the line of reflection
Ry axis, line of reflection is the y axis
line of reflection
2) COUNT how far each point is from the line of reflection
A is 3 units form y axis
B is on the y axis
C is 3 units form y axis 3) Each image point should be the same distance on the other side of the line
**Because B is on the line of reflection it does not move
9.2 ReflectionsDetermine the line of reflection from the graph of the preimage and image, then draw the line of reflection.
F
G
H
F'H'
G'
Steps:1) Pick and point and its image
F and F'2) COUNT (or use distance formula) to find the distance the points are from each other
3) The line of reflection is 1/2 the distance from the preimage point to the image point (divide by 2)
4) Count the distance from a point to find the line of reflection
**6 ÷ 2 = 3
line of reflection
ANSWER: y = 2
9.2 Reflections Practice WS Name
1. Ryaxis2. Rxaxis
3. Ry = 2 4. Rx = 1
5.6.
7. 8.
9. 10.
Determine the line of reflection from the graph of the preimage and image, then draw the line of reflection.
11. 12.