Int Math 2 Section 5-3 1011

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Parallel Lines and Transversals

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SECTION 5-3Parallel Lines and Transversals

Tuesday, January 25, 2011

ESSENTIAL QUESTIONS

How do you identify angles formed by parallel lines and transversals?

How do you identify and use properties of parallel lines?

Where you’ll see this:

Construction, safety, navigation, music

Tuesday, January 25, 2011

VOCABULARY1. Parallel Lines:

2. Parallel Planes:

3. Skew Lines:

4. Transversal:

5. Interior Angles:

6. Exterior Angles:

Tuesday, January 25, 2011

VOCABULARY1. Parallel Lines: Coplanar lines that do not intersect

2. Parallel Planes:

3. Skew Lines:

4. Transversal:

5. Interior Angles:

6. Exterior Angles:

Tuesday, January 25, 2011

VOCABULARY1. Parallel Lines: Coplanar lines that do not intersect

2. Parallel Planes: Planes that do not intersect

3. Skew Lines:

4. Transversal:

5. Interior Angles:

6. Exterior Angles:

Tuesday, January 25, 2011

VOCABULARY1. Parallel Lines: Coplanar lines that do not intersect

2. Parallel Planes: Planes that do not intersect

3. Skew Lines: Noncoplanar lines that do not intersect and are not parallel

4. Transversal:

5. Interior Angles:

6. Exterior Angles:

Tuesday, January 25, 2011

VOCABULARY1. Parallel Lines: Coplanar lines that do not intersect

2. Parallel Planes: Planes that do not intersect

3. Skew Lines: Noncoplanar lines that do not intersect and are not parallel

4. Transversal: A line that intersects two other coplanar lines at different points

5. Interior Angles:

6. Exterior Angles:

Tuesday, January 25, 2011

VOCABULARY1. Parallel Lines: Coplanar lines that do not intersect

2. Parallel Planes: Planes that do not intersect

3. Skew Lines: Noncoplanar lines that do not intersect and are not parallel

4. Transversal: A line that intersects two other coplanar lines at different points

5. Interior Angles: Angles formed in between two coplanar lines when intersected by a transversal

6. Exterior Angles:

Tuesday, January 25, 2011

VOCABULARY1. Parallel Lines: Coplanar lines that do not intersect

2. Parallel Planes: Planes that do not intersect

3. Skew Lines: Noncoplanar lines that do not intersect and are not parallel

4. Transversal: A line that intersects two other coplanar lines at different points

5. Interior Angles: Angles formed in between two coplanar lines when intersected by a transversal

6. Exterior Angles: Angles formed outside two coplanar lines when intersected by a transversal

Tuesday, January 25, 2011

VOCABULARY7. Alternate Interior Angles:

8. Same-side Interior Angles:

9. Alternate Exterior Angles:

10. Corresponding Angles:

Tuesday, January 25, 2011

VOCABULARY7. Alternate Interior Angles: Interior angles on opposite sides of a

transversal; these angles are congruent (parallel lines)

8. Same-side Interior Angles:

9. Alternate Exterior Angles:

10. Corresponding Angles:

Tuesday, January 25, 2011

VOCABULARY7. Alternate Interior Angles: Interior angles on opposite sides of a

transversal; these angles are congruent (parallel lines)

8. Same-side Interior Angles: Interior angles on the same side of a transversal; these angles are supplementary (parallel lines)

9. Alternate Exterior Angles:

10. Corresponding Angles:

Tuesday, January 25, 2011

VOCABULARY7. Alternate Interior Angles: Interior angles on opposite sides of a

transversal; these angles are congruent (parallel lines)

8. Same-side Interior Angles: Interior angles on the same side of a transversal; these angles are supplementary (parallel lines)

9. Alternate Exterior Angles: Exterior angles on opposite sides of a transversal; these angles are congruent (parallel lines)

10. Corresponding Angles:

Tuesday, January 25, 2011

VOCABULARY7. Alternate Interior Angles: Interior angles on opposite sides of a

transversal; these angles are congruent (parallel lines)

8. Same-side Interior Angles: Interior angles on the same side of a transversal; these angles are supplementary (parallel lines)

9. Alternate Exterior Angles: Exterior angles on opposite sides of a transversal; these angles are congruent (parallel lines)

10. Corresponding Angles: These angles will have the same position around a transversal and the lines it intersects with; these angles are congruent (parallel lines)

Tuesday, January 25, 2011

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b

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Tuesday, January 25, 2011

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b

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Interior Angles:

Tuesday, January 25, 2011

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b

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Interior Angles: 3, 4, 5, 6

Tuesday, January 25, 2011

1 23 4

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a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles:

Tuesday, January 25, 2011

1 23 4

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a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Tuesday, January 25, 2011

1 23 4

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a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Alternate Interior Angles:

Tuesday, January 25, 2011

1 23 4

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a

b

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Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Alternate Interior Angles: 3 & 6, 4 & 5

Tuesday, January 25, 2011

1 23 4

8765

a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Alternate Interior Angles: 3 & 6, 4 & 5

Same-side Interior Angles:

Tuesday, January 25, 2011

1 23 4

8765

a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Alternate Interior Angles: 3 & 6, 4 & 5

Same-side Interior Angles: 3 & 5, 4 & 6

Tuesday, January 25, 2011

1 23 4

8765

a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Alternate Interior Angles: 3 & 6, 4 & 5

Same-side Interior Angles: 3 & 5, 4 & 6

Alternate Exterior Angles:

Tuesday, January 25, 2011

1 23 4

8765

a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Alternate Interior Angles: 3 & 6, 4 & 5

Same-side Interior Angles: 3 & 5, 4 & 6

Alternate Exterior Angles: 1 & 8, 2 & 7

Tuesday, January 25, 2011

1 23 4

8765

a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Alternate Interior Angles: 3 & 6, 4 & 5

Same-side Interior Angles: 3 & 5, 4 & 6

Alternate Exterior Angles: 1 & 8, 2 & 7Corresponding Angles:

Tuesday, January 25, 2011

1 23 4

8765

a

b

m

Interior Angles: 3, 4, 5, 6

Exterior Angles: 1, 2, 7, 8

Alternate Interior Angles: 3 & 6, 4 & 5

Same-side Interior Angles: 3 & 5, 4 & 6

Alternate Exterior Angles: 1 & 8, 2 & 7Corresponding Angles: 1 & 5, 2 & 6, 3 & 7, 4 & 8

Tuesday, January 25, 2011

Parallel Line Postulates

Tuesday, January 25, 2011

Parallel Line Postulates

If two parallel lines are intersected by a transversal, then corresponding angles are congruent

Tuesday, January 25, 2011

Parallel Line Postulates

If two parallel lines are intersected by a transversal, then corresponding angles are congruent

If two lines are intersected by a transversal so that corresponding angles are congruent, then the lines are parallel

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

4x +10 = 2x + 20

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

4x +10 = 2x + 20 −2x −2x

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

4x +10 = 2x + 20 −2x −2x −10 −10

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

4x +10 = 2x + 20 −2x −2x −10 −10

2x =10

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

4x +10 = 2x + 20 −2x −2x −10 −10

2x =10 2 2

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

4x +10 = 2x + 20 −2x −2x −10 −10

2x =10 2 2 x = 5

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

4x +10 = 2x + 20 −2x −2x −10 −10

2x =10 2 2 x = 5

m∠AEF = (4(5) +10)°

Tuesday, January 25, 2011

EXAMPLE 1

In the figure, AB CD

. If m∠AEF = (4x +10)° and

m∠EFD = (2x + 20)°, find m∠AEF .

A B

F

E

C D

H

G

*

*

4x +10 = 2x + 20 −2x −2x −10 −10

2x =10 2 2 x = 5

m∠AEF = (4(5) +10)°

m∠AEF = 30°

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

7x + 40 = 2x + 20

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

7x + 40 = 2x + 20 −2x −2x

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

7x + 40 = 2x + 20 −2x −2x −40 −40

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

7x + 40 = 2x + 20 −2x −2x −40 −40

5x = −20

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

7x + 40 = 2x + 20 −2x −2x −40 −40

5x = −20 5 5

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

7x + 40 = 2x + 20 −2x −2x −40 −40

5x = −20 5 5 x = −4

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

7x + 40 = 2x + 20 −2x −2x −40 −40

5x = −20 5 5 x = −4

m∠BEF = (7(−4) + 40)°

Tuesday, January 25, 2011

EXAMPLE 2

In the figure, AB CD

. If m∠FEB = (7x + 40)° and

m∠HFD = (2x + 20)°, find m∠BEF .

A B

F

E

C D

H

G

*

*

7x + 40 = 2x + 20 −2x −2x −40 −40

5x = −20 5 5 x = −4

m∠BEF = (7(−4) + 40)°

m∠BEF =12°

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

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Complementary:

Supplementary:

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

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Complementary:None

Supplementary:

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

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Complementary:None

Supplementary:

∠2 and ∠4

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

1 23 4

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Vertical:

Adjacent:

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

1 23 4

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Vertical:

Adjacent:

∠2 and ∠4

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

1 23 4

8765

Vertical:

Adjacent:

∠2 and ∠4

∠1 and ∠4

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

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Interior:

Alternate Interior:

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

1 23 4

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Interior:

Alternate Interior:

∠3 and ∠6

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

1 23 4

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Interior:

Alternate Interior:

∠3 and ∠6

∠3 and ∠4

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

1 23 4

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Same-side Interior:

Exterior:

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

1 23 4

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Same-side Interior:

Exterior:

∠1 and ∠7

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

1 23 4

8765

Same-side Interior:

Exterior:

∠1 and ∠7

∠3 and ∠5

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

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Alternate Exterior:

Corresponding:

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

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Alternate Exterior:

Corresponding:

∠1 and ∠5

Tuesday, January 25, 2011

EXAMPLE 3Refer to the figure. For each type of angle relationship mentioned, list a pair of angles that would satisfy the

relationship.

For example, ∠1 and ∠2 are supplementary.

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Alternate Exterior:

Corresponding:

∠1 and ∠5

∠1 and ∠8

Tuesday, January 25, 2011

PROBLEM SET

Tuesday, January 25, 2011

PROBLEM SET

p. 204 #1-35 odd

“The talent of success is nothing more than doing what you can do, well.” - Henry W. Longfellow

Tuesday, January 25, 2011