PRE-ALGEBRA

Warm up for Lesson 9-1

PRE-ALGEBRA

Introduction to Geometry: Points, Lines, and Planes (9-1)

What is a point, line, plane, line segment, and ray?

PRE-ALGEBRA

What are parallel and skew lines?

Introduction to Geometry: Points, Lines, and Planes (9-1)Parallel lines are two lines that lie in the same plane but neverintersect (like railroad tracks). You use the symbol II to indicate two lines are parallel. Skew lines are lines that lie in different planes (think walls or boards). Skew lines could be parallel, but they do not intersect, since they are on different planes (lines on different boards will never intersect, even if they aren’t parallel).

Example: In the figure below, segments MN and TP are parallel, or

MN II TP

and segments MN and RS are skew (on different planes)

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LESSON 9-1

Additional Examples

Introduction to Geometry: Points, Lines, and Planes

Use the figure to name each of the following.

H, I, J, and K Name a point with a capital letter.

a. four points

b. four different segments

c. five other names for KI

d. five different rays

, and OI, IO, OK, KO

HO Name a segment by its endpoints., HJ, KI, and OI

IK There is one line pictured. It has several names.

The first letter names the endpoint of the ray.

HO, OJ, KI , OK, and JH

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MP, OP, QT, ST

MQ, NR, OS

MN, NO, QR, RS

You are looking directly down into a wooden crate. Name each of the following.

a. four segments that intersect PT

b. three segments parallel to PT

c. four segments skew to PT

LESSON 9-1

Additional Examples

Introduction to Geometry: Points, Lines, and Planes

PRE-ALGEBRA

Draw two intersecting lines. Then draw a segment that is parallel to one of the intersecting lines.

Use the lines on notebook or graph paper.

First draw two lines that intersect.

Then draw a segment that is parallel to one of the lines.

LESSON 9-1

Additional Examples

Introduction to Geometry: Points, Lines, and Planes