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Big Ideas Math: Modeling Real Life, Grade 8

BI

Big Ideas Math: Modeling Real Life, Grade 8 View details

Chapter Review

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Exercise 4 Page 131

Use the relationship of angles between parallel lines.

40^(∘), see solution.

Practice makes perfect

Let's consider the given diagram.

angles

To find the measure of ∠ 2, note that the given angle and ∠ 2 form a straight line.

angles

This means that they are supplementary and the sum of their measures is 180^(∘). With this information, we can finally find the measure of ∠ 2. m∠ 2+ 140^(∘)=180^(∘) ⇕ m∠ 2=40^(∘)

Subchapter links

1 Parallel Lines and Transversals p.131

2 Angles of Triangles p.132

3 Angles of Polygons p.132-133

4 Using Similar Triangles p.133