3.1 identify pairs of lines and angles

3.13.1 Identify Pairs of Lines and AnglesBell Thinger

ANSWER D2. What is the intersection of AD and DB?

1. Name a line that does not intersect AD.ANSWER BC

3.1

3.1Example 1Think of each segment in the figure as part of a line. Which line(s) or plane(s) in the figure appear to fit the description?a. Line(s) parallel to CD and containing

point ASOLUTION

AB , HG , and EF all appear parallel to CD , but only AB contains point A.

a.

3.1

SOLUTION

b. Line(s) skew to CD and containing point A

Both AG and AH appear skew to CD and contain point A.

b.

Example 1Think of each segment in the figure as part of a line. Which line(s) or plane(s) in the figure appear to fit the description?

3.1

SOLUTION

c. BC, AD , DE , and FC all appear perpendicular to CD , but only AD contains point A.

c. Line(s) perpendicular to CD and containing point A

Example 1Think of each segment in the figure as part of a line. Which line(s) or plane(s) in the figure appear to fit the description?

3.1

SOLUTION

d. Plane(s) parallel to plane EFG and containing point A

d. Plane ABC appears parallel to plane EFG and contains point A.

Example 1Think of each segment in the figure as part of a line. Which line(s) or plane(s) in the figure appear to fit the description?

3.1

3.1

MD FE a.

Example 2

Photography

The given line markings show how the roads are related to one another.

Name a pair of parallel lines.

a.

SOLUTION

3.1

SOLUTION

Name a pair of perpendicular lines.

b.

b. MD BF

Example 2

Photography

The given line markings show how the roads are related to one another.

3.1

SOLUTION

Is FE AC ? Explain.c.

FE is not parallel to AC , because MD is parallel to FE and by the Parallel Postulate there is exactly one line parallel to FE through M.

c.

Example 2

Photography

The given line markings show how the roads are related to one another.

3.1Guided Practice1. Name the lines through point H

that appear skew to CD.

ANSWER AH , EH

3.1Guided Practice2.Can you use the

Perpendicular Postulate to show that AC is not perpendicular to BF ? Explain why or why not.

Yes; Since A is not on MD and MD is to BF, the Perpendicular Postulate guarantees that there is exactly one line through a point perpendicular to a line, so AC can not be perpendicular to BF also.

ANSWER

3.1

3.1Example 3

SOLUTION

a. 51and 62and 73and 84and

b. 72and 54and

c. 81and 63and

Identify all pairs of angles of the given type.

d. 52and 74and

a. Corresponding

b. Alternate interior

c. Alternate exterior

Consecutive interiord.

3.1Guided PracticeClassify the pair of numbered angles.

ANSWER

corresponding angles

3.

3.1Classify the pair of numbered angles.

4.

ANSWER

alternate exterior angles.

Guided Practice

3.1Classify the pair of numbered angles.

5.

ANSWER

alternate interior angles.

Guided Practice

3.1Exit Slip1. Name the pairs of

corresponding angles .

2. Name the pairs of alternate interior angles .

3. Name the pairs of consecutive interior angles .

2 and 4; 6 and 8

1 and 3; 5 and 7;ANSWER

ANSWER 2 and 7; 3 and 6

ANSWER 2 and 3; 6 and 7

3.14. The figure shows a painting easel. Does AB appear

to be parallel, perpendicular, or skew to CD?

ANSWER

Parallel

Exit Slip

3.1

Homework

Pg 154-156# 20, 21, 33, 34, 35