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CHAPTER 3LINES AND
ANGLES
PARALLEL LINES
• Def: line that do not intersect.
• Illustration:
• Notation: l || m AB || CD
lm
A
B
C
D
p. 129
28
Examples of Parallel Lines
• Hardwood Floor
• Opposite sides of windows, desks, etc.
• Parking slots in parking lot
• Parallel Parking
• Streets: Laramie & LeClaire
Examples of Parallel Lines
• Streets: Belmont & School
PERPENDICULAR LINES
• Def: Lines that intersect to form a right angle.
• Illustration:
• Notation: m n
• Key Fact: 4 right angles are formed.
m
n
p. 79
29
Ex. of Perpendicular Lines• Window panes• Streets: Belmont and Cicero
• Def: a line that intersects two lines at different points
• Illustration:
Transversal
t
p. 131
30
Vertical Angles
• Two angles that are opposite angles.
1 2
3 4
5 6
7 8
t
1 42 35 86 7
Vertical Angles
• Find the measures of the missing angles
125
?
?
55
t
55
125
Supplementary Angles/Linear Pair
• Two angles that form a line (sum=180)
1 2
3 4
5 6
7 8
t
5+6=1806+8=1808+7=1807+5=180
1+2=1802+4=1804+3=1803+1=180
Supplementary Angles/Linear Pair
• Find the measures of the missing angles
? 72
?
t
108
108 180 - 72
Corresponding Angles
• Two angles that occupy corresponding positions.
Top Left
t
Top Left
Top Right
Top Right
Bottom Right
Bottom Right
Bottom Left
Bottom Left
1 52 63 74 8
1 2
3 4
5 6
7 8
p. 131 & 143
30
Corresponding Angles
• Find the measures of the missing angles
145
?
t
35
145
Alternate Interior Angles
• Two angles that lie between parallel lines on opposite sides of the transversal
t
3 64 5
1 2
3 4
5 6
7 8
p. 131 & 143
30
Alternate Interior Angles
• Find the measures of the missing angles
82
?
t
98 82
Alternate Exterior Angles
• Two angles that lie outside parallel lines on opposite sides of the transversal
t
2 71 8
1 2
3 4
5 6
7 8
p. 131 & 143
30
Alternate Exterior Angles
• Find the measures of the missing angles
120
?
t
60 120
Consecutive Interior Angles
• Two angles that lie between parallel lines on the same sides of the transversal
t
3 +5 = 1804 +6 = 180
1 2
3 4
5 6
7 8
p. 131 & 143
30
Consecutive Interior Angles
• Find the measures of the missing angles
?
t
135
45
180 - 135
HW
P. 132 – 133
• # 6 – 9
• # 21 – 26
P. 146 - 147
• #7 - 17
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