Download SB En Geom 4-2 Completed.notebook

SB En Geom 4­2 Completed.notebook
September 28, 2012
Lesson 4­2 Triangle Congruence by SSS and SAS
How many noncongruent triangles can you form with the three sides?
Oct 2­8:19 AM
Postulate 4­1
Side­Side­Side (SSS) Postulate
If three sides of one triangle are congruent to the three sides of another triangle, then the two triangles are congruent.
Picture
Expl 1. Write a flow proof to show the triangles congruent.
B
C
A
D
Oct 2­8:23 AM
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SB En Geom 4­2 Completed.notebook
September 28, 2012
Ckpt 1.
F
Given: HF ≅ HJ, FG ≅ JK,
H is the midpoint of GK
Prove: ΔFGH ≅ ΔJKH
1.
1.
2.
2.
3.
3.
G
J
H
K
Oct 2­8:28 AM
included is used when referring to the angles and sides of a triangle
­ a side is between two angles
­ an angle is between two sides
example...
M
N
O
Oct 2­8:29 AM
2
SB En Geom 4­2 Completed.notebook
September 28, 2012
How many triangles can you form with two sides and an included angle?
Oct 2­8:31 AM
Postulate 4­2
Side­Angle­Side (SAS) Postulate
If two sides and the included angle of one triangle are congruent to the two sides and the included angle of another triangle, then the two triangles are congruent.
Oct 2­8:33 AM
3
SB En Geom 4­2 Completed.notebook
September 28, 2012
Expl 2. What other information do you need to prove the triangles congruent by SAS?
S
R
T
K
A
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Ckpt 2. What other information do you need to prove ΔABC ≅ ΔCDA?
7
6
B
D
7
C
Oct 2­8:35 AM
Expl 3 ­ Can you prove ΔRED ≅ ΔCAT? Explain.
A
EC
R
T
D
Ckpt 3 ­ Can you prove ΔAEB ≅ ΔDBC? Explain.
A
B
C
E
D
Oct 2­8:40 AM
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SB En Geom 4­2 Completed.notebook
September 28, 2012
Homework
Lesson 4‐2
2‐42E, 44‐46
Oct 2­8:42 AM
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