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The Leaner Twins. Lefty . Righty . Graphing Transformations 2. Reflection - flipping a shape across a line so it faces the opposite direction. y. 4. figure. image. B’. B. 3. C. C’. 2. 1. A’. A. x. D. D’. -4. -3. -2. -1. 1. 2. 3. 4. -1. -2. -3. -4.
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The Leaner Twins Lefty Righty
Graphing Transformations 2 Reflection - flipping a shape across a line so it faces the opposite direction.
y 4 figure image B’ B 3 C C’ 2 1 A’ A x D D’ -4 -3 -2 -1 1 2 3 4 -1 -2 -3 -4 A reflection of ABCD in the y-axis
y 4 B 3 2 C 1 A x D -4 -3 -2 -1 1 2 3 4 D’ A’ -1 -2 C’ -3 B’ -4 A reflection of ABCD in the x-axis A reflection of ABC in the y-axis
y mirror line 4 B 3 2 C 1 A x D C’ -4 -3 -2 -1 1 2 3 4 D’ -1 -2 B’ -3 A’ -4 A reflection of ABCD across a mirror line
How are a figure and its reflection image alike? They are congruent.
How are a figure and its reflection image different? They have different orientations. If ABCD is read clockwise, A’B’C’D’ is read counter-clockwise.
How do you identify a reflection? Check that corresponding points are the same distance from the mirror line.
y Coordinates 4 B’ B 3 A(-4,1) B(-2,3) C(0,2) D(-1,0) C C’ 2 1 A’ A x D D’ -4 -3 -2 -1 1 2 3 4 A’(4,1) B’(2,3) C’(0,2) D’(1,0) -1 -2 -3 -4 A reflection of ABCD in the y-axis
What patterns do you see in the coordinates of the figure and its image? • y-coordinates are the same because the shape does not go up or down • x-coordinates are the opposite because the shape was reflected in the y-axis
y Coordinates 4 B 3 A(-4,1) B(-2,3) C(0,2) D(-1,0) 2 C 1 A x D -4 -3 -2 -1 1 2 3 4 D’ A’ -1 A’(-4,-1) B’(-2,-3) C’(0,-2) D’(-1,0) -2 C’ -3 B’ -4 A reflection of ABCD in the x-axis A reflection of ABC in the y-axis
What patterns do you see in the coordinates of the figure and its image? • x-coordinates are the same because the shape does not go left or right • y-coordinates are the opposite because the shape was reflected in the x-axis
y Coordinates 4 B 3 A(-4,1) B(-2,3) C(0,2) D(-1,0) 2 C 1 A x D C’ -4 -3 -2 -1 1 2 3 4 D’ -1 A’(1,-4) B’(3,-2) C’(2,0) D’(0,-1) -2 B’ -3 A’ -4 A reflection of ABCD across a mirror line
What pattern do you see in the coordinates of the figure and its image? • x-coordinates and y-coordinates switch places
y 4 A 3 B D 2 1 x -4 -3 -2 -1 1 2 3 4 C -1 -2 -3 -4 Reflect ABCD across the y-axis and x-axis.
y 4 A 3 B D 2 1 x -4 -3 -2 -1 1 2 3 4 C -1 -2 -3 -4 Reflect ABCD across the mirror line.