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Lesson Plans and Worksheets for Grade 8

Lesson Plans and Worksheets for all Grades

More Lessons for Grade 8

Common Core For Grade 8

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

### Lesson 3 Outcome

### Lesson 3 Summary

### NYS Math Module 3 Grade 8 Lesson 3

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

Lesson Plans and Worksheets for Grade 8

Lesson Plans and Worksheets for all Grades

More Lessons for Grade 8

Common Core For Grade 8

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

Download Worksheets for Grade 8, Module 3, Lesson 3

• 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.

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.

Classwork

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

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.

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