John Smith's List: Geometry Transformations

• the same size
• original image
• A reflection is a flip over a line
• • Trick: When rotating over any axis, keep the letter of the axis you are rotating the same and change the sign of the other letter.
• X-Axis
• If the mirror line is the x-axis, just change each (x,y) into (x,-y)
• Y-Axis

• each (x,y) into (-x,y)

     

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• Multiple   Choice Practice
• Choose the best answer
• y = -x  o
• same  or opposite orientation
• positive angl

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• factor
• stretches or shrinks a function
• stretches or shrinks a function
• horizontal and vertical lines
• same scal
• same scale
• (0,0)
• factor

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• scale factor
• coordinates of the image of
• (with center  at
• origi

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• translation.
• "every point of the pre-image is moved the same distance in the same direction to form the image.
• T(x, y) = (x+5, y+3).
• flip"
• over a line
• reflection

• • Reflection over x-axis:      T(x, y) = (x, -y) 

   
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    Reflection over y-axis:      T(x, y) = (-x, y) 

   
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    Reflection over line y = x:  T(x, y) = (y, x) 
• around a
• "spinning
• rotation
• fixed point
• tation 180° around the origin:  T(x, y) = (-x, -y)

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• Sliding".
• looks exactly the same