Straight Lines

1
Straight Lines
2
Angles
VERTEX
MEASURE
3
Angles
4
Angles
5
Angles
6
Angles
7
Angles
8
Angles
9
Angles
10
Angles
11
Angles and Parallel Lines
180 - q
q
q
180 - q
12
Polygons
IRREGULAR
REGULAR
13
Polygons
VERTEX
IRREGULAR
REGULAR
14
Polygons
INTERIOR ANGLE
IRREGULAR
REGULAR
15
Polygons

• Sum of angles (n - 2)180
• n number of sides
• n number of angles

16
Polygons

• Example What is the angle in a regular pentagon?

q ?
17
Polygons

• Example What is the angle in a regular pentagon?

Sum of angles (n - 2)180 5q (5 - 2)
180 5q 540 q 108
18
Triangles

• Sum of angles (n - 2)180
• Sum of angles (3 - 2)180
• Sum of angles 180

19
Area of a Triangle
h
b
h
b
20
Area of a Triangle
21
Pythagorean Theorem

• a2 b2 c2
• Right Triangles Only!

c
a
b
22
Special Right Triangles

• 30 - 60 - 90

c 2b
60
b c/2
30
a
23
Special Right Triangles

• 45 - 45 - 90

45
a b
45
b a
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Special Right Triangles

• 3 - 4 - 5

c 5
a 3
b 4