Chapter 3.1 Properties of Parallel Lines

2.0 Students write geometric proofs4.0 Students prove basic theorems involving

congruence7.0 Students prove and use theorems involving the

properties of parallel lines cut by a transversal

Vocabulary

• Transversal – a line that intersects two coplanar lines at two distinct points.

Vocabulary

• Interior angles – Angles that are in between the two lines cut by a transversal

Vocabulary

• Exterior angles – Angles that are outside the two lines cut by a transversal

Vocabulary

• Alternate interior angles

Vocabulary

• Alternate exterior angles

Vocabulary

• Corresponding Angles – angles that can “over-lap”

Vocabulary

• Same Side Interior Angles

Vocabulary

• Same Side Exterior Angles

Corresponding Angles Postulate

• If a transversal intersects two parallel lines, then corresponding angles are congruent

Alternate Interior Angles Theorem

• If a transversal intersects two parallel lines, then alternate interior angles are congruent

Same-Side Interior Angles Theorem

• If a transversal intersects two parallel lines, then same side interior angles are supplementary

Alternate Exterior Angles Theorem

• If a transversal intersects two parallel lines, then alternate exterior angles are congruent

Same-side Exterior Angles Theorem

• If a transversal intersects two parallel lines, then same side exterior angles are supplementary

Examples – interwrite activity

• Random problems with different theorems

Parallelogram Problem

Homework

• Pg 131 #1-7, 11-17, 23-25