Dilations in the Coordinate Plane. What is a dilation? A better name is a projection. The hands...
-
Upload
bonnie-smith -
Category
Documents
-
view
213 -
download
1
Transcript of Dilations in the Coordinate Plane. What is a dilation? A better name is a projection. The hands...
Dilations in the Coordinate Plane
What is a dilation?
• A better name is a projection.• The hands differ only in size, so dilations produce similar figures.• This dilation is an enlargement since the dilation
makes the image larger.• The original is called the pre-image and the
projection is called the image.• The “light source” of the projection is called the
center of the dilation
Dilations on the Coordinate Plane
• A dilation with its center at the origin (0,0) is obtained by multiplying the x and y coordinates of the pre-image points by the scale factor.• We use the variable “k” to represent the scale factor.• (x,y) -> (kx,ky) is the coordinate notation for a dilation centered at the
origin.• For us, k will be a positive number.• When k is greater than 1, the dilation is an enlargement.• When k is less than 1, the dilation is a reduction.
Example• Perform the specified
dilation and classify it as an enlargement or a reduction.
Since ½ is less than 1, we know it will be a reduction before we even begin.)
Pre-image Image
A(-2,4) A’(-1,2)
B(6,8) B’(3,4)
C(2,0) C’(1,0)
Complete Worksheet 6.6A for tomorrow.