Examples of Dilations

Examples, videos, and solutions to help Grade 8 students learn some examples of dilations.

New York State Common Core Math Grade 8, Module 3, Lesson 3

Worksheets for Grade 8

Lesson 3 Outcome

• Students know that dilations map circles to circles and ellipses to ellipses with the same shape.
  
• Students know that to shrink or magnify a dilated figure back to its original size from center 0 with scale factor r you must dilate the figure by a scale factor of 1/r.

Lesson 3 Summary

Dilations map circles to circles and ellipses to ellipses.
If a figure is dilated by scale factor r, to bring the dilated figure back to the original size we must dilate it by a scale factor of 1/r. For example, if a scale factor is r = 4, then to bring a dilated figure back to the original size, we must dilate it by a scale factor r = 1/4.

NYS Math Grade 8, Module 3, Lesson 3

Classwork
Example 1 Dilate circle A, from center 0 at the origin by a scale factor r = 3.

• Show Video

• Show Video

Exercises 1 - 2

1. Dilate ellipse E, from center 0 at the origin of the graph, with scale factor r = 2. Use as many points as necessary to develop the dilated image of ellipse E.
2. What shape was the dilated image?

Example 2
In the picture below, we have a triangle ABC, that has been dilated from center 0, by a scale factor of r = 1/3 It is noted by A’B’C'.

Example 3
In the picture below we have a triangle DEF, that has been dilated from center r = 0, by a scale factor of r = 4. It is noted by D’E’F’.
Exercise 3
Triangle ABC has been dilated from center 0 by a scale factor of r = 1/4 denoted by triangle A’B’C’. Using a ruler, verify that it would take a scale factor r = 4 of from center 0 to map triangle A’B’C’ onto triangle ABC.

Check out our most popular games!

We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page.