Unit 2: Parallel and Perpendicular Lines

Unit 2 Learning Targets 

LT 2-1: I can determine the measure of angles on Parallel Lines.

LT 2-2: I can prove 2 lines are parallel.

LT 2-3: I can determine the measure of an angle in a triangle.

LT 2-4: I can write the equation of a parallel or perpendicular line.

LESSON 2-1

Parallel Lines

When parallel lines are cut by a transversal, the special angle pairs that are formed are congruent, supplementary, or both.

Help Videos:

●       What Is the Corresponding Angles Postulate?

●       How Do You Find Missing Angles in a Transversal Diagram?

Practice:

2-1 Math XL

LESSON 2-2

Proving Lines Parallel

Pairs of congruent or supplementary angles formed when two lines are cut by a transversal can be used to prove the lines are parallel.

Help Videos:

●       How Do You Use Parallel and Perpendicular Theorems to Prove a Relationship Between Two Lines?

●       How Do You Construct a Line Parallel to Another Line Through a Given Point?

Practice:

2-2 Math XL

LESSON 2-2

Proving Lines Parallel

Pairs of congruent or supplementary angles formed when two lines are cut by a transversal can be used to prove the lines are parallel.

Help Videos:

●       How Do You Use Parallel and Perpendicular Theorems to Prove a Relationship Between Two Lines?

●       How Do You Construct a Line Parallel to Another Line Through a Given Point?

Practice:

2-2 Math XL

LESSON 2-3

Parallel Lines and Triangle Angle Sums

The sum of the measures of the interior angles of a triangle is 180°, and the measure of an exterior angle of a triangle is equal to the sum of the measures of the remote interior angles.

Help Videos:

●       How Do You Find Missing Angles in a Triangle with Variables?

●       What Is the Triangle Sum Theorem?

Practice:

2-3 Math XL

LESSON 2-4

Slopes of Parallel and Perpendicular Lines

Two parallel lines have equal slopes. The product of the slopes of perpendicular lines is –1.

Help Videos:

●       How Do You Write an Equation of a Line in Slope-Intercept Form If You Have One Point and a Parallel Line?

●       How Do You Write an Equation of a Line in Slope-Intercept Form If You Have One Point and a Perpendicular Line?

Practice:

2-4 Math XL

Unit 2 Vocabulary

●        flow proof