Unit 2 Day 1: Parallel Lines & Transversals

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Unit 2: Lines, Angles, and Parallelism

Day 1: Parallel Lines & Transversals

Today's Objective

Warm-Up: Foundational Ideas

A Plane is a flat surface that extends forever.

Coplanar means on the same plane.

Intersect means to cross or meet at a point.

Vocabulary Focus

Parallel Lines: Coplanar lines that never intersect.

Skew Lines: Non-coplanar lines that never intersect.

Parallel Planes: Two planes that do not intersect (like a floor and a ceiling).

Transversal: A line that intersects two or more coplanar lines.

Real World Connection

Think of a highway overpass.

The path of the overpass and the road below it are on different planes and will never meet.

This is a real-world example of skew lines.

I Do: Identifying a Transversal

Line t is the transversal because it intersects two other coplanar lines, l and m.

lmt

I Do: Parallel vs. Skew Lines

Line AB is parallel to CD. (They are coplanar and don't intersect)

Line AB is skew to HG. (They are non-coplanar and don't intersect)

ABEFCDHG

I Do: Parallel Planes

The top plane (ABFE) is parallel to the bottom plane (CDHG). They will never intersect.

ABEFCDHG

We Do: Let's Try Together

Using the cube diagram...

1. Name a line parallel to line EH.

2. Name a line skew to line EH.

3. Name a plane parallel to plane BCGF.

You Do: Practice Time!

Now, open your interactive notes to Day 1 and complete the "You Do" section.

Independent Practice

Try these problems on your own, starting with green.

Green Level

Using the cube, name a line segment that is parallel to segment AB.

Yellow Level

Using the cube, name two different line segments that are skew to segment EH.

Red Level

True or False: Line segments AE and DH are skew. Explain your reasoning.

Exit Ticket

On a piece of paper, name one pair of parallel lines and one pair of skew lines from the cube diagram.

ABEFCDHG

Unit 2: Lines, Angles, and Parallelism

Day 1: Parallel Lines & Transversals

Warm-Up: Foundational Ideas

A Plane is a surface that extends forever.

Coplanar means on the plane.

Intersect means to or meet at a point.

Vocabulary Focus

Parallel Lines: lines that never intersect.

Skew Lines: lines that never intersect.

Parallel Planes: Two planes that do not .

Transversal: A line that intersects two or more lines.

Reference Diagram for Practice

Use this cube for the practice problems below.

ABEFCDHG

I Do: Examples

Parallel vs. Skew: Line AB is parallel to . Line AB is skew to .

Parallel Planes: Plane ABFE is parallel to plane .

We Do: Let's Try Together

1. Name a line parallel to line EH:

2. Name a line skew to line EH:

3. Name a plane parallel to plane BCGF:

Independent Practice

Green: Name a segment parallel to AB:

Yellow: Name two segments skew to EH: and

Red: True or False: Segments AE and DH are skew.

Explain:

Exit Ticket

Name one pair of parallel lines from the cube:

Name one pair of skew lines from the cube: