In this Grade 8 lesson from Big Ideas Math, Course 3, students learn to identify and classify angles formed when parallel lines are cut by a transversal, including corresponding angles, interior angles, and exterior angles. Students apply the property that corresponding angles are congruent and use supplementary angle relationships to find missing angle measures. This lesson supports Common Core standard 8.G.5 within Chapter 3: Angles and Triangles.
Section 1
Parallel Lines
Parallel Lines are lines in the same plane that never intersect, no matter how far they are extended. Parallel lines are always the same distance apart and run in the same direction. We use the symbol to indicate that two lines are parallel. If line is parallel to line , we write .
Section 2
Definition: Transversals
A transversal is a line that intersects two or more other lines at distinct points. When a transversal intersects two lines, it creates eight angles at the two intersection points.
Section 3
Corresponding Angles are Congruent
When a transversal intersects two parallel lines, corresponding angles are congruent. Corresponding angles occupy the same relative position at each intersection point.
Expand to review the lesson summary and core properties.
Section 1
Parallel Lines
Parallel Lines are lines in the same plane that never intersect, no matter how far they are extended. Parallel lines are always the same distance apart and run in the same direction. We use the symbol to indicate that two lines are parallel. If line is parallel to line , we write .
Section 2
Definition: Transversals
A transversal is a line that intersects two or more other lines at distinct points. When a transversal intersects two lines, it creates eight angles at the two intersection points.
Section 3
Corresponding Angles are Congruent
When a transversal intersects two parallel lines, corresponding angles are congruent. Corresponding angles occupy the same relative position at each intersection point.