Chapter 3.1 Properties of Parallel Lines 2.0 Students write geometric proofs 4.0 Students prove basic theorems involving congruence 7.0 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