CHAPTER 3 3-1 lines and angles

Problem of the day

Objectives

Identify parallel, perpendicular, and skew lines.

Identify the angles formed by two lines and a transversal.

Lines • What kind of different lines you know?

• What are parallel lines ?• Solution: Lines that go next to each other and they will

never intersect .• Examples are?

What are perpendicular lines ?

Solution: Lines that intersect and form a 90 degree angle.

Example are?

Lines • What are skew lines?• Solution: A re lines that are not parallel and do not

intersect.• Examples?

Example#1• Identify each of the following.

A. a pair of parallel segments

LM ||QR

B. a pair of skew segments

KN and PQ

C. a pair of perpendicular segments

NS SP

a pair of parallel planes

plane NMR || plane KLQ

Student guided practice• Identify each of the following.

a pair of parallel segments

BF || EJ

a pair of skew segments

BF and DE are skew.

a pair of perpendicular segments

BF FJ

Example#2

Give an example of each angle pair.

corresponding angles

1 and 5

alternate interior angles

3 and 5

C. alternate exterior angles

1 and 7

same-side interior angles

3 and 6

Student guided practice• Give an example of each angle pair.

corresponding angles

1 and 3

alternate interior angles

2 and 7

alternate exterior angles

1 and 8

Transversal lines • What is a transversal line?• Solution: Is a line that intersects two coplanar lines at two

different points • How can you identify a transversal line?• Solution: To determine which line is the transversal for a

given angle pair, locate the line that connects the vertices.

Example#3• Identify the transversal and classify each angle pair.

A. 1 and 3

transversal l corr. s

B. 2 and 6

transversal nalt. int s

C. 4 and 6

transversal malt. ext s

Student guided practice • Identify the transversal and classify the angle pair 2 and 5 in the diagram.

Homework!!• Go to page 148 in your book and di problems 2-12

Closure • Today we learn about lines and the different pair of angles

in a transversal• Next class we are going to see chapter 3-2