1 geometry section 4-2d corresponding parts pg. 274 be ready to grade 4-2c quiz tuesday!!! exam...
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Geometry Section 4-2DGeometry Section 4-2D
Corresponding PartsCorresponding Parts
Pg. 274Pg. 274
Be ready to grade 4-2CBe ready to grade 4-2CQuiz Tuesday!!!Quiz Tuesday!!!
Exam Review Questions Exam Review Questions Monday.Monday.
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Answers for 4-2CAnswers for 4-2C
1. Complimentary2. True3. True4. C – 50.2o, S – 140.2o
5. C – 41o, S – 131o
6. C – 53 ½o , S – 143 ½o
7. C – 23o, S – 113o
8. mDBC = 52 ½o, mDBE = 127 ½o
9. mABD = 47o, mDBC = 43 o
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Answers for 3-3C – cont.Answers for 3-3C – cont.10.mEBD = 136o, mABD = 46o
11.mDBC = 52o, mABD = 38o
12.mDBC = 52o, mABD = 38o
13.57o
Book:16.No, if the window ledge is
straight, both angles will = 90o.17.35o
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ExploreExplore
Statements: Reasons
c. AEB and CED are rt. angles
Given
Right angles are
b. AE CE
Givend. ABE CDE
Given
a. AEB CED
f. AEB CED SAA
e. AB CD Def. of triangles
E
C
A
B
D
Given: AE CEABE CDEAEB and CED are rt. ’s
Prove: AB CD
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Theorem:Theorem:
Corresponding parts of congruent triangles are congruent.
CPCTC
If you can prove that triangles are congruent using a previous postulate, then you can prove that all parts of
the triangles are congruent by using CPCTC.
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Properties of Congruence:Properties of Congruence:Properties of Congruence
Examples
Reflexive
Symmetric
Transitive
AB AB
If 1 2 then 2 1
If WX XY and XY YZ then WX YZ
A
B
AB AB
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Try It:Try It:
a.
b.
1 marked angle and 1 marked side + the reflexive property.
SV VU, VST VUT and SVT UVT
T
V
S U
How can you prove that the triangles are congruent by using the SAS Postulate?
Which additional pairs of sides and angles could you then prove congruent by using CPCTC?
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ExercisesExercises
R S
T
A B
C
1. Write a triangle congruence statement for the triangles shown.ABC RST
b. Which congruence postulate can be used to prove the triangles are congruent? SSS
c. Once you prove the triangles are congruent, how can you show that C T? CPCTC
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Statements Reasons
a. GFH EFH d. GFH EFH
e. EH GHb. EF GFc. HF HF
Given
Given
Reflexive
SSS
CPCTC
E
G
FH
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R
U
S
T
Statements: Reasons
RUS TSU
Given
Given
RU ST
Reflexive Property US US
SAS
SUT USR
RSU TUS
CPCTC
RS || UT Alt. Int. ‘s Theorem
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