- Dilations can enlarge or reduce a shape.
- When a dilation has occurred, the image is similar to the pre-image (same shape, different size).
- In order to dilate a shape, you need:
- Scale Factor (k): A number that determines how much larger or smaller the image will be compared to the pre-image.
- Center of Dilation (x, y): The fixed point from which all points of the pre-image are scaled.
- Coordinate Rules:
- Dilation centered at the origin (0, 0):
- Enlarge: k is greater than 1. Example k = 2. (x, y) → (2x, 2y)
- Reduce: k is between 0 and 1. Example k = 1/2. (x, y) → (1/2x, 1/2y)
- Dilation NOT centered at (0,0):
- No rule. You must count from the center of dilation to each point. Then, multiply the counts by the scale factor.
Parent Tip: Review the logic above to help your child master the concept of geometry dilation worksheets.
