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6-8 Grade 8 Unit 2 Lesson 8

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K-5 Math •6-8 Math 9-12 Math

Course

Grade 6 Grade 7 •Grade 8

Unit

Unit 1 •Unit 2 Unit 3 Unit 4 Unit 5 Unit 6 Unit 7 Unit 8 Unit 9

Lesson

Lesson 1 Lesson 2 Lesson 3 Lesson 4 Lesson 5 Lesson 6 Lesson 7 •Lesson 8 Lesson 9 Lesson 10 Lesson 11 Lesson 12 Lesson 13

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6-8
9-12

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Grade 7
Grade 8

Accelerated 6
Accelerated 7

Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
Unit 6
Unit 7
Unit 8
Unit 9

Lesson 1
Lesson 2
Lesson 3
Lesson 4
Lesson 5
Lesson 6
Lesson 7
Lesson 8
Lesson 9
Lesson 10
Lesson 11
Lesson 12
Lesson 13

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Unit 2, Lesson 8

Similar Triangles

Grade 8

Practice

Problem 1
Student Task Statement
For each pair of triangles, some of the angle measures are given in degrees. Use the information to decide if the triangles are similar or not. Explain how you know.

Triangle A: 53, 71, ; Triangle B: 53, 71,

Triangle C: 90, 37, ; Triangle D: 90, 53,

Triangle E: 63, 45, ; Triangle F: 14, 71,

Triangle G: 121, , ; Triangle H: 70, ,

Lesson 8 Resources

Student Materials

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Problem 2

Student Task Statement

Draw 2 equilateral triangles that are not congruent.
Measure the side lengths and angles of your triangles. Are the 2 triangles similar?
Do you think 2 equilateral triangles will be similar always, sometimes, or never? Explain your reasoning.

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Problem 3

Student Task Statement

In the figure, line segment is parallel to line segment .

Explain why triangle is similar to triangle .

Two triangles. First, A, B C. Then triangle A, D E where D lies on side A, B and E lies on side A, E.<br>

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Problem 4

ForLesson 4: Dilations on a Square Grid

Student Task Statement

The quadrilateral in the diagram is a parallelogram.

Let be the image of after applying a dilation centered at a point (not shown) with scale factor 3.

Quadrilateral P Q R S on a square grid.

Which of the following is true?

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Problem 5

ForLesson 6: Describing Transformations

Student Task Statement

Describe a sequence of transformations for which Quadrilateral P is the image of Quadrilateral Q.

Two quadrilaterals in an x y plane.<br>

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