Download 3.1 Parallel Lines and Transversals

August 05, 2015
3.1 Parallel Lines and
Transversals
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Parallel Lines: Two coplaner lines that never intersect
Transversal: a line that intersects two or more lines in
different points
parallel lines
transversal
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Alternate Angles
angles that lie on opposite sides of the transversal
exterior: lie on outside of parallel lines
interior: lie on inside of parallel lines
Alternate Exterior
<1, <8 and <2, <7
Alternate Interior
<3, <6 and <5, <4
ALWAYS
CONGRUENT!!!
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Consecutive Angles (Same-side)
angles that lie on the inside of the parallel lines
angles that lie on the same side of the transversal
Consecutive Angles
<3, <5 and <4, <6
ALWAYS
SUPPLEMENTARY!!!
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Corresponding Angles
angles that lie on the same side of the transversal
one angle lies inside parallel lines, one angle lies outside
Angles lie in the same position, just on different lines.
Corresponding Angles
<1, <5 and <2, <6
<3, <7 and <4, <8
ALWAYS
CONGRUENT!!!
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Line AB is parallel to line CD, line s is parallel to line t. Find
all the numbered angles if m<1 = 100o.
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a
r
s
1 2
9 10
12 11
4 3
b
5 6
8 7
1.) Find x if m<3 = 4x + 6 and
m<11 = 126.
13 14
16 15
a is parallel to b
r is parallel to s
2.) Find x if m<1 = 100 and
m<8 = 2x + 10.
3.) Find y if m<11 = 3y - 5 and m<14 = 2y + 20.
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ALWAYS IDENTIFY THE ANGLE PAIR FIRST!!! THEN
SET THE EXPRESSIONS EQUAL OR ADD THEM TO 180!!!
EQUAL
Alternate Interior
Alternate Exterior
Corresponding
Vertical
ADD TO 180
Consecutive
Linear Pair
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