7-2: Reasoning and Parallel Lines

Key Concept

Corresponding Angles and Parallel Lines If the corresponding angles formed by two lines and a transversal are congruent, then the lines are parallel.

Alternate Interior Angles and Parallel Lines If the alternate interior angles formed by two lines and a transversal are congruent, then the lines are parallel.

Part 1

Intro

The symbol || means “is parallel to.” If line m is parallel to line n, you write m || n.

Example Justifying Parallel Lines with Corresponding Angles

Can you conclude that a || b? Justify your reasoning.

Lines a and b crossed by transversal t; the angle below line a and to the left of transversal t measures 59°; the angle below line b and to the left of transversal t measures 59°.


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Table of Contents

Digits, Grade 8, Volume 1, Homework Helper Unit A: Number and Operations Unit B: Proportionality Unit C: Expressions, Equations, and Relationships English/Spanish Glossary Formulas Math Symbols Formulas Measures Properties