Chapter Review
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To obtain the image of a vertex after a dilation with scale factor k, multiply its coordinates by k.
Graph:
Type of Dilation: Reduction
A dilation can be an enlargement, a reduction, or the same size as the preimage. Which type of dilation it is depends on the value of the scale factor k.
| Enlargement | k>1 |
|---|---|
| Reduction | 0 |
| Same | k=1 |
ccc Preimage & & Image [0.5em] (x,y)& ⇒ & ( kx, ky) Now, let's find the coordinates of the vertices of BCDE after a dilation with a scale factor k= 13. Since our scale factor is less than 1, the dilation is a reduction.
| Dilation With Scale Factor k= 13 | ||
|---|---|---|
| Preimage | Multiply by k | Image |
| B(3,3) | ( 1/3(3), 1/3(3)) | B'(3/3,3/3)=(1,1) |
| C(3,6) | ( 1/3(3), 1/3(6)) | C'(3/3,6/3)=(1,2) |
| D(6,6) | ( 1/3(6), 1/3(6)) | D'(6/3,6/3)=(2,2) |
| E(6,3) | ( 1/3(6), 1/3(3)) | E'(6/3,3/3)=(2,1) |