Plans and Worksheets for Grade 8
Plans and Worksheets for all Grades
Lessons for Grade 8
Common Core For Grade 8
Videos, examples, and solutions to help Grade 8 students learn how to understand that a two-dimensional figure is similar to another if the second can be obtained from the first by a sequence of rotations, reflections, translations, and dilations; given two similar two-dimensional figures, describe a sequence that exhibits the similarity between them.
Common Core: 8.G.4
Suggested Learning Targets
- I can define similar figures as corresponding angles are congruent and
corresponding side lengths are proportional.
- I can recognize the symbol for similar.
- I can apply the concept of similarity to write similarity statements
- I can reason that a 2-D figure is similar to another if the second can be obtained
by a sequence of rotations, reflections, translation or dilation
- I can describe the sequence of rotations, reflections, translations, or dilations that
exhibits the similarity between 2-D figures using words and/or symbols.
Describe sequences of transformations to prove two figures are similar or congruent (8.G.4)
Similarity 1 (8.G.4)
In this lesson you will learn how to prove that two figures are congruent by describing a sequence of rotations, reflections or translations.
Two figures are congruent if you can translate, rotate, and/or reflect one shape to get the other. (Angle measures and side lengths are the same).
Two figures are similar if you can if you can translate, rotate, reflect and/or dilate one shape to get the other. (Angle measures and side lengths may be different).
Transformations and Congruent versus Similar Figures
Similar figures have the same shape, but not the same size.
1) All angles are congruent.
2) Sides are proportional, not congruent, and are found by multiplying by a scaling factor.
How different sequences of transformations can result in figures that are congruent or similar to the original figure?
Lesson on Similarity
Dilation followed by a congruence shows two figures are similar.
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