1. CHAPTER 3
LINES AND ANGLES
Is it Chapter 3 for us too?

2. PARALLEL LINES 28 Def: line that do not intersect. Illustration:
Notation: l || m AB || CD A B C D l m
Is that a complete definition?
I may give two lines that in the present dimension may not intersect but that won’t make them parallel
The idea of not meeting even after extending needs to be highlighted
p. 129

3. Examples of Parallel Lines
Hardwood Floor
Opposite sides of windows, desks, etc.
Parking slots in parking lot
Parallel Parking
Streets: Laramie & LeClaire
What’s Laramie & LeClaire?
How are they relevant to students we are targeting?

4. Examples of Parallel Lines
Streets: Belmont & School

5. 29
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

6. Ex. of Perpendicular Lines
Window panes
Streets: Belmont and Cicero

7. 30
Transversal
Def: a line that intersects two lines at different points
Illustration: t
p. 131

8. Vertical Angles 1   4 2   3 5   8 6   7
Two angles that are opposite angles. t
1   4
2   3
5   8
6   7 1 2 3 4
Vertical Angles are the angles opposite each other when two lines cross. "Vertical" in this case means they share the same Vertex (corner point), not the usual meaning of up-down. That is not coming through in the PPT 5 6 7 8

9. Vertical Angles Find the measures of the missing angles t 125  ?
55  ?
55 

10. Supplementary Angles/ Linear Pair
Two angles that form a line (sum=180) 1 2 3 4 5 6 7 8 t
1+2=180
2+4=180
4+3=180
3+1=180
5+6=180
6+8=180
8+7=180
7+5=180

11. Supplementary Angles/ Linear Pair
Find the measures of the missing angles t ?
108 
72  ?
108 

12. Corresponding Angles 1   5 2   6 3   7 4   8 30
Two angles that occupy corresponding positions. t
1   5
2   6
3   7
4   8
Top Left
Top Right 1 2 3 4 5 6 7 8
Bottom Left
Bottom Right
Top Left
Top Right
Bottom Left
Bottom Right
p. 131 & 143

13. Corresponding Angles Find the measures of the missing angles t 145 
35  ?
145 

14. Alternate Interior Angles30
Alternate Interior Angles
Two angles that lie between parallel lines on opposite sides of the transversal t
3   6
4   5 1 2 3 4 5 6 7 8
p. 131 & 143

15. Alternate Interior Angles
Find the measures of the missing angles t
82 
98  ?
82 

16. Alternate Exterior Angles30
Alternate Exterior Angles
Two angles that lie outside parallel lines on opposite sides of the transversal t
2   7
1   8 1 2 3 4 5 6 7 8
p. 131 & 143

17. Alternate Exterior Angles
Find the measures of the missing angles t
120  ?
60 
120 

18. Consecutive Interior Angles30
Consecutive Interior Angles
Two angles that lie between parallel lines on the same sides of the transversal t
3 +5 = 180
4 +6 = 180 1 2 3 4 5 6 7 8
p. 131 & 143

19. Consecutive Interior Angles
Find the measures of the missing angles t
135  ?
45 

20. HW
P. 132 – 133
# 6 – 9
# 21 – 26 P
#7 - 17

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