# Understanding Dilations and Scale Factors

Learn about dilations, scale factors, and the center of dilation, with examples of enlargements, congruent figures, and reductions.

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## About Understanding Dilations and Scale Factors

PowerPoint presentation about 'Understanding Dilations and Scale Factors'. This presentation describes the topic on Learn about dilations, scale factors, and the center of dilation, with examples of enlargements, congruent figures, and reductions.. The key topics included in this slideshow are . Download this presentation absolutely free.

## Presentation Transcript

2. Definitions Dilation - a transformation in which every point P has an image P' placed on OP so that and OP' = k * OP Center of Dilation – the point from which an original figure is dilated. Scale Factor - the ratio of the image length to the corresponding original length.

3. Scale Factor • If the scaled factor is greater than 1, then it is an enlargement (k>1) . • If the scaled factor is equal to 1, then it is a congruent figure (k=1) • If the scale factor is less than 1, then it is a reduction (k<1) .

4. Corresponding distances 4 2 = = 2 Image Distance Original Distance = k Scale Factor 2 > 1 This dilation is an enlargement .

5. Corresponding distances 2 3 = Image Distance Original Distance = k Scale Factor 2/3 < 1 This dilation is an reduction .

6. Example: 1. Rectangle W ’ X ’ Y ’ Z ’ is the image of rectangle WXYZ after a dilation. a. Find the scale factor of the dilation. b. Tell whether the image is a reduction or an enlargement .

7. Example: 2.

8. Example: 3.

9. Reduction, Enlargement, or Congruent? 1. K = 4 2. K = ½ 3. K = 1 4>1 Enlargement ½ <1 Reduction Congruent

10. Matching A. K = ¼ B. K = 3 C. K = 2/7 D. K = 1 E. K = 5 F. K = 3/8 Reduction Enlargement Congruent