Dilation Notes

In 8th grade the 4 types of transformations are translation, reflection, rotation, and dilation. We haven't learned about_______ yet. 

• translations
• reflections
• rotations
• dilations

Dilation is a transformation that changes the size of a shape, and in doing so also changes its position. 

• Interesting tell me more
• ...

Dilation changes the shape in which of the following ways

• Size only
• Position only
• Size and position
• Size, position and orientation

Dilation is the only transformation that does not maintain congruence. All three of the previous transformations we discussed did.

• Fascinating
• ...

Which of the following transformations is the only one that does NOT maintain congruence of with the original shape.

• Translation
• Reflection
• Rotation
• Dilation

Dilation is the only transformation whose algebraic representation includes numbers. this is because dilation's are created by multiplying the original shape by a scale factor.

• Scale Factors? tell me more!
• ...

The algebraic representation of a dilation's with a scale factor of 3 would be ( x , y) → ( 3x , 3y)

• So the scale factor becomes the coefficient of x & y. That's easy.
• ...

Which algebraic representation represents a dilation with a scale factor of 7 ? 

• ( x , y) → ( 7x , y)
• ( x , y) → ( x , 7y)
• ( x , y) → ( 3.5x , 3.5y)
• ( x , y) → ( 7x , 7y)

Which algebraic representation represents a dilation with a scale factor of 0.4 ? 

• ( x , y) → ( 0.4x , y)
• ( x , y) → ( x , 0.4y)
• ( x , y) → ( 4x , 4y)
• ( x , y) → ( 0.4x , 0.4y)

Which algebraic representation represents a dilation with a scale factor of ¾ ?

• ( x , y) → ( ¾x , y)
• ( x , y) → ( x , ¾y)
• ( x , y) → ( ¾x , ¾y)
• ( x , y) → ( x +¾ , y +¾)