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Angles and Transversals.notebook
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October 08, 2013
Warm Up
Angles and Transversals.notebook
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October 08, 2013
t
ml
Transversal
Transversal: A line that intersects two or more lines at different points.
Note: The lines the transversal intersects do not need to be parallel.
Angles and Transversals.notebook
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October 08, 2013
With transversals, we have exterior, interior and alternating angles...
Angles and Transversals.notebook
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Alternate Interior Anglesare on opposite sides of the transversal
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are on the same side of the transversal
Consecutive Interior Angles
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Hint: Consecutive means one right after another.
If two parallel lines are cut by a transversal,
then the two pairs of sameside interior angles are supplementary.
m<1 + m<4 = 180 degrees and m<2 + m<3 = 180 degrees
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Alternate Exterior Angles
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are on opposite sides of the transversal
If two parallel lines are cut by a transversal,
then the two pairs of alternate exterior angles are congruent.
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Corresponding Angles
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are in the exact location on the parallel lines
Elevator Problem
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Exterior Angles: Interior Angles: Consecutive Interior Angles: Alternate Interior Angles: Corresponding Angles: Alternate Exterior Angles:
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ml
Transversal
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Describe the angles when the lines are ll:
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a.) <7 & < 11: corresponding
b.) <9 & <2: consecutive interior
c.) <7 and <12: corresponding
d.) <8 and <10: alternate interior
e.) <4 and <8: consecutive interior
f.) <2 and <12: alternate exterior
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52 43
91
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Describe the angles when the lines are not ll:
erase for answers
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October 08, 2013
a.) <1 & < 8: alternate exterior
b.) <7 & <10: alternate interior
c.) <8 and <12: corresponding
d.) <1 and <5: corresponding
e.) <4 and <6: consecutive interior
f.) <8 and <9: alternate interior
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3 42
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l
m
Describe the angles when the lines are not ll:
Erase
erase for answers
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Angles and Transversals.notebook
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October 08, 2013
Warm Up
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Angles and Parallel Lines
If two parallel lines are cut by a transversal, then...(a) corresponding angles are congruent(b) alternate interior angles are congruent(c) alternate exterior angles are congruent(d) consecutive interior angles are supplementary
*The converses are true, also.*
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7 8
l
m
k
l || m<1 ≅ <6<4 ≅ <8<2 ≅ <5<3 ≅ <7
<4 ≅ <6<3 ≅ <5
<1 ≅ <8<2 ≅ <7
m<4 + m<5 = 180o
m<3 + m<6 = 180o
corresponding angles
alternateinterior
alternate exterior
consecutiveinterior
erase for answers
Transversal
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Identifying angles
alternateinterior
consecutiveinterior
alternateexterior
corresponding
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EXample1234 5
678
l
m
t l || m
1. m<7 = 100, m<3= ____2. m<7 = 95, m<6= ____3. m<1 = 120, m<5= ____4 m<4 = 20, m<7= ____5. m<3 = 140, m<8= ____6. m<4 = 30, m<1= ____7. m<4 = 40, m<2= ____8. m<7 = 125, m<4= ____9. If l t, m<3 = _____10. If m<1 + m<3 = 230, m<6 = _____
T
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line p is parallel to line qm < 1 = 107m < 11 = 48
p
q
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