Download CHAPTER 4: CONGRUENT TRIANGLES

CHAPTER 4:
CONGRUENT TRIANGLES
Section 4-2:
Some Ways to Prove Triangles
Congruent
TRIANGLE CONGRUENCE
When two triangles are congruent, the six
parts of one triangle are congruent to the
six corresponding parts of the other
triangle.
There are ways to prove triangles congruent
by comparing only three pairs of
corresponding parts, which is the focus of
this section.
POSTULATE 12:
SSS POSTULATE
Postulate 12 (SSS Postulate):
If three sides of one triangle are congruent
to three sides of another triangle, then the
triangles are congruent.
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5
3
3
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POSTULATE 13:
SAS POSTULATE
Postulate 13 (SAS Postulate):
If two sides and the included angle of one
triangle are congruent to two sides and the
included angle of another triangle, then the
triangles are congruent.
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6
65
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6
POSTULATE 14:
ASA POSTULATE
Postulate 14 (ASA Postulate):
If two angles and the included side of one
triangle are congruent to two angles and
the included side of another triangle, then
the triangles are congruent.
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PRACTICE
Decide whether you can deduce by SSS, SAS, or ASA
Postulate that the two triangles are congruent.
1.
1. Triangles are
congruent by SSS.
2.
2. Triangles are not
congruent.
3.
3. Triangles are
congruent by SAS.
CLASSWORK/HOMEWORK
• Classwork: Pg. 123-124 Classroom
Exercises 1-10
• Homework: Pg. 124-125 Written Exercises
1-16