Transcript Slide 1

Do Now 3/15/12
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Take out HW from last night.
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Copy HW in your planner.
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Text p. 312, #1-16 all, 21
Text p. 318, #10-23 all, 27 & 28
In your journal, describe how to use a
protractor. Use step-by-step
instructions on how to measure an
angle.
Homework
Text p. 312, #1-16 all, 21
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1) Q, R, S
2) QS, RT
3) plane QRS
4) UQ, UT, US
5) QU, RU, SU
6) BA & BC,
AE & CE ,
AD & CD
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7) D, E, F
8) DE, EF
9) plane DEF
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10) DE, FD, EF
11) DE, EF, DF
12) AF & BC, AE & BD,
AB & ED, FE & CD
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13) Plane ABC contains
points A, B, C; lines AB
& BC; line segments AB,
AC, ∾ rays AB, BA,
BC, CB, & CA. Plane
ACD contains points A,
C, D; line segments AC,
AD, & CD; and ray CA
Homework
Text p. 312, #1-16 all, 21
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14) 6; WX , WY , WZ , XY, XZ, YZ,
15) answer vary
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16)
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21) C
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Objective
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SWBAT identify angles and angle pairs
Section 8.2 “Classifying Angles”
Angle
two rays with a common
endpoint.
D
Sides
C
Vertex
E
Naming Angles
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The following angle can be named in three ways:
B
C
A
BAC
CAB
Vertex
A
Types of Angles
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Right angle = 90 degrees
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Acute angle = less than 90 degrees
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Obtuse angle = more than 90 degrees
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Straight angle = exactly 180 degrees
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MEASURE of  A is
m A as
written
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.
PROTRACTOR can be used to
approximate the measure of an
angle.
Using a Protractor
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Find mABC
= 130°
A
B
C
Using a Protractor
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Find mABC
= 70°
A
B
C
What is the measure of a
straight line (in degrees)?
180°
B
Supplementary Angles
When two angles form a straight
line, the sum of their measures is
180°
180°
150°
30°
Complementary Angles
When two angles form a right
angle, the sum of their measures
is 90°
64°
90°
26°
Use the diagram to tell whether the angles are
complementary, supplementary, or neither.
OMP and PMQ
P
O
N
Q
30°
60°
R
M
OMP = 60° and PMQ = 30° and 30°+60° = 90°
therefore, they are complementary.
Use the diagram to tell whether the angles are
complementary, supplementary, or neither.
NMO and OMR
P
Q
O
N
165°
15°
R
M
NMO = 15° and OMR= 165° and 15°+165° = 180°
therefore, they are supplementary.
Use the diagram to tell whether the angles are
complementary, supplementary, or neither.
BAC and EAF
D
E
C
B
35°
35°
A
BAC = 35° and EAF= 35° and 35°+35° = 70°
therefore, they are neither.
F
Finding Angle Measures
Angles A and B are complementary. If mA is
56°, what is the mB?
Since A and B are complementary, mA + mB =
90°.
mA + mB = 90°
56° + mB = 90°
– 56°
– 56°
mB = 34°
Substitute 56° for mA.
Subtract 56° from both
sides.
The measure of B = 34°.
Finding Angle Measures
Angles P and Q are supplementary. If mP is
32°, what is the mQ?
Since P and Q are supplementary, mP + mQ
= 180°.
mP + mQ = 180°
32° + mQ = 180°
– 32°
– 32°
mQ = 148°
Substitute 32° for mP.
Subtract 32° from both
sides..
The measure of Q = 148°.
Homework
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Text p. 318, #10-23 all, 27 & 28