Download 1.4 Angle Notes

1.4 Angle Notes
D.I.R.T?
2. Skew lines are __?__ coplanar
1. Round 67.763
a) to the nearest tenth_____
b) to the nearest hundredth _____
c) to the nearest whole number ____
3. Identify the following, using the diagram
H
G
E
a) Parallel lines
F
b) Skew lines
D
B
C
c) Intersecting lines
A
1.4 Measuring Angles
Objective: To find the measures of angles
What is an angle???
Angle­ Formed by two rays with the same endpoint.
Vertex­ the endpoint of an angle Sides­ Each ray of the angle
How do you NAME angles???
E
Name the following angles:
A
2
B
1
D
C
F
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1.4 Angle Notes
How do you CLASSIFY angles???
2
1.4 Angle Notes
3
1.4 Angle Notes
Complementary vs. Supplementary Angles
Complements: 1550
650
250
Supplements: 4
1.4 Angle Notes
Postulate 1­8: Angle Addition Postulate
­ Adjacent angle measures can be added together to form a large angle measure.
C
A
m < ABC + m < CBD = m < ABD
D B
EX) m <ZTF = 125
m <UTF = 50 Find m <ZTU
Z
U
T
EX 2)
F
E
C
D
F
m < CDE= x+4 m<EDF=x+20.
Find x=
m<CDE
m<EDF
5
1.4 Angle Notes
Congruent angles­ Angles that have the exact same measure.
Angle Bisector ­ A ray that divides an angles into two congruent angles. EX. 4) BX bisects <ABC. If m<ABX = 5x, m<XBC = 3x+10, find x and m<ABC. A
X
B
C
Assignment: Worksheet
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