Geometry Section 3-2 1112

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Transcript of Geometry Section 3-2 1112

SECTION 3-2ANGLES AND PARALLEL LINES

Wednesday, December 14, 2011

ESSENTIAL QUESTIONS

HOW DO YOU USE THEOREMS TO DETERMINE THE RELATIONSHIPS BETWEEN SPECIFIC PAIRS OF ANGLES?

HOW DO YOU USE ALGEBRA TO FIND ANGLE MEASUREMENTS?

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

CORRESPONDING ANGLES POSTULATE

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

CORRESPONDING ANGLES POSTULATE

IF TWO PARALLEL LINES ARE CUT BY A TRANSVERSAL, THEN EACH PAIR OF

CORRESPONDING ANGLES IS CONGRUENT.

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

CORRESPONDING ANGLES POSTULATE

IF TWO PARALLEL LINES ARE CUT BY A TRANSVERSAL, THEN EACH PAIR OF

CORRESPONDING ANGLES IS CONGRUENT.

∠1 ≅ ∠5

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

ALTERNATE INTERIOR ANGLES THEOREM

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

ALTERNATE INTERIOR ANGLES THEOREM

IF TWO PARALLEL LINES ARE CUT BY A TRANSVERSAL, THEN EACH PAIR OF

ALTERNATE INTERIOR ANGLES IS CONGRUENT.

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

ALTERNATE INTERIOR ANGLES THEOREM

IF TWO PARALLEL LINES ARE CUT BY A TRANSVERSAL, THEN EACH PAIR OF

ALTERNATE INTERIOR ANGLES IS CONGRUENT.

∠4 ≅ ∠6

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

CONSECUTIVE INTERIOR ANGLES THEOREM

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

CONSECUTIVE INTERIOR ANGLES THEOREM

IF TWO PARALLEL LINES ARE CUT BY A TRANSVERSAL, THEN EACH PAIR OF CONSECUTIVE INTERIOR ANGLES IS

SUPPLEMENTARY.

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

CONSECUTIVE INTERIOR ANGLES THEOREM

IF TWO PARALLEL LINES ARE CUT BY A TRANSVERSAL, THEN EACH PAIR OF CONSECUTIVE INTERIOR ANGLES IS

SUPPLEMENTARY.

∠4 AND ∠5 ARE SUPPLEMENTARY

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

ALTERNATE EXTERIOR ANGLES THEOREM

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

ALTERNATE EXTERIOR ANGLES THEOREM

IF TWO PARALLEL LINES ARE CUT BY A TRANSVERSAL, THEN EACH PAIR OF ALTERNATE EXTERIOR ANGLES IS

CONGRUENT.

Wednesday, December 14, 2011

POSTULATES AND THEOREMS

ALTERNATE EXTERIOR ANGLES THEOREM

IF TWO PARALLEL LINES ARE CUT BY A TRANSVERSAL, THEN EACH PAIR OF ALTERNATE EXTERIOR ANGLES IS

CONGRUENT.

∠2 ≅ ∠7

Wednesday, December 14, 2011

EXAMPLE 1

IN THE FIGURE, m∠4 = 51°. FIND THE MEASURE OF EACH ANGLE. GIVE A JUSTIFICATION TO

YOUR ANSWER.a. m∠2

b. m∠3

c. m∠6

Wednesday, December 14, 2011

EXAMPLE 1

IN THE FIGURE, m∠4 = 51°. FIND THE MEASURE OF EACH ANGLE. GIVE A JUSTIFICATION TO

YOUR ANSWER.a. m∠2

51°; VERTICAL ANGLESWITH ∠4

b. m∠3

c. m∠6

Wednesday, December 14, 2011

EXAMPLE 1

IN THE FIGURE, m∠4 = 51°. FIND THE MEASURE OF EACH ANGLE. GIVE A JUSTIFICATION TO

YOUR ANSWER.a. m∠2

51°; VERTICAL ANGLESWITH ∠4

b. m∠3129°; SUPPLEMENTARY ANGLES WITH ∠4

c. m∠6

Wednesday, December 14, 2011

EXAMPLE 1

IN THE FIGURE, m∠4 = 51°. FIND THE MEASURE OF EACH ANGLE. GIVE A JUSTIFICATION TO

YOUR ANSWER.a. m∠2

51°; VERTICAL ANGLESWITH ∠4

b. m∠3129°; SUPPLEMENTARY ANGLES WITH ∠4

c. m∠651°; ALTERNATE INTERIOR ANGLES WITH ∠4

Wednesday, December 14, 2011

EXAMPLE 2

USE THE FIGURE, IN WHICH a||b, m∠2 = 125°, AND c||d||e, TO FIND THE MEASURE OF EACH NUMBERED ANGLE. PROVIDE A REASON FOR

THE ANSWER FOR EACH MEASURE.

Wednesday, December 14, 2011

EXAMPLE 2

USE THE FIGURE, IN WHICH a||b, m∠2 = 125°, AND c||d||e, TO FIND THE MEASURE OF EACH NUMBERED ANGLE. PROVIDE A REASON FOR

THE ANSWER FOR EACH MEASURE.

m∠1 = 125°; VERTICAL

WITH ∠2

Wednesday, December 14, 2011

EXAMPLE 2

USE THE FIGURE, IN WHICH a||b, m∠2 = 125°, AND c||d||e, TO FIND THE MEASURE OF EACH NUMBERED ANGLE. PROVIDE A REASON FOR

THE ANSWER FOR EACH MEASURE.

m∠1 = 125°; VERTICAL

WITH ∠2m∠3 = 55°; CONSECUTIVE

INTERIOR WITH ∠2

Wednesday, December 14, 2011

EXAMPLE 2

USE THE FIGURE, IN WHICH a||b, m∠2 = 125°, AND c||d||e, TO FIND THE MEASURE OF EACH NUMBERED ANGLE. PROVIDE A REASON FOR

THE ANSWER FOR EACH MEASURE.

m∠1 = 125°; VERTICAL

WITH ∠2m∠3 = 55°; CONSECUTIVE

INTERIOR WITH ∠2m∠4 = 125°; CONSECUTIVE

INTERIOR WITH ∠3

Wednesday, December 14, 2011

EXAMPLE 2

USE THE FIGURE, IN WHICH a||b, m∠2 = 125°, AND c||d||e, TO FIND THE MEASURE OF EACH NUMBERED ANGLE. PROVIDE A REASON FOR

THE ANSWER FOR EACH MEASURE.

m∠1 = 125°; VERTICAL

WITH ∠2m∠3 = 55°; CONSECUTIVE

INTERIOR WITH ∠2m∠4 = 125°; CONSECUTIVE

INTERIOR WITH ∠3

m∠5 = 55°; SUPPLEMENTARY WITH ∠4

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

a. IF m∠2 = 2x − 10 AND

m∠6 = x + 15, FIND x.

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

a. IF m∠2 = 2x − 10 AND

m∠6 = x + 15, FIND x.

2x − 10 = x + 15

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

a. IF m∠2 = 2x − 10 AND

m∠6 = x + 15, FIND x.

2x − 10 = x + 15−x −x

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

a. IF m∠2 = 2x − 10 AND

m∠6 = x + 15, FIND x.

2x − 10 = x + 15−x −x +10+10

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

a. IF m∠2 = 2x − 10 AND

m∠6 = x + 15, FIND x.

2x − 10 = x + 15−x −x +10+10

x = 25

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

a. IF m∠2 = 2x − 10 AND

m∠6 = x + 15, FIND x.

2x − 10 = x + 15−x −x +10+10

x = 25

SINCE THE ANGLES ARE CORRESPONDING, THEY ARE CONGRUENT, MEANING THEY ARE

EQUAL.

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

b. IF m∠7 = 4(y − 25) AND

m∠1 = 4y, FIND y.

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

b. IF m∠7 = 4(y − 25) AND

m∠1 = 4y, FIND y.

4(y − 25) + 4y = 180

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

b. IF m∠7 = 4(y − 25) AND

m∠1 = 4y, FIND y.

4(y − 25) + 4y = 1804y − 100 + 4y = 180

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

b. IF m∠7 = 4(y − 25) AND

m∠1 = 4y, FIND y.

4(y − 25) + 4y = 1804y − 100 + 4y = 180

8y − 100 = 180

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

b. IF m∠7 = 4(y − 25) AND

m∠1 = 4y, FIND y.

4(y − 25) + 4y = 1804y − 100 + 4y = 180

8y − 100 = 1808y = 280

Wednesday, December 14, 2011

EXAMPLE 3

USE THE FIGURE TO FIND THE INDICATED VARIABLE. EXPLAIN YOUR REASONING.

b. IF m∠7 = 4(y − 25) AND

m∠1 = 4y, FIND y.

4(y − 25) + 4y = 1804y − 100 + 4y = 180

8y − 100 = 1808y = 280

y = 35

Wednesday, December 14, 2011

CHECK YOUR UNDERSTANDING

CHECK OUT PROBLEMS 1-10 ON PAGE 181.

Wednesday, December 14, 2011

PROBLEM SET

Wednesday, December 14, 2011

PROBLEM SET

P. 181 #11-35 ODD

“YOU CAN FOOL TOO MANY OF THE PEOPLE TOO MUCH OF THE TIME.” - JAMES THURBER

Wednesday, December 14, 2011