Page 90 - Math Course 3 (Book 2)

ASA and AAS Postulates
Mo. 9

Lesson 5

KEY CONCEPTS:

1. Use the ASA Postulate to test for triangle
congruence.
2. Use the AAS Theorem to test for triangle
congruence.

MO. 9 - L5a

Triangle Congruence: POSTULATE 9.5
ASA and AAS Angle-Angle-Side Congruence

If two angles and a nonincluded side of one triangle
Vocabulary A-Z are congruent to the corresponding two angles and
side of a second triangle, then the two triangles are
Let us learn some vocabulary congruent.

Abbreviations: AAS
included side K A
The two sides or rays that form an angle of the
triangle.

The included sides of The included sides of J L C B
angle ABC in △ABC are angle FDE in △FDE are
BA and BC. DF and DE. △JKL ≅ △CAB

B
D
F CONCEPT SUMMARY

C Method Use when...
A E
All corresponding parts of one
Definition of
POSTULATE 9.3 Congruent triangle are congruent to the
Triangles corresponding parts of the other
triangle.
Angle-Side-Angle Congruence The three sides of one triangle are

If two angles and the included side of one triangle SSS congruent to the three sides of the
are congruent to two angles and the included side other triangle.
of another triangle, then the triangles are congruent. Two sides and the included angle
of one triangle are congruent to two
SAS
Abbreviations: ASA C sides and the included angle of the
other triangle.
T W Two angles and the included side
of one triangle are congruent to two
ASA
angle and the included side of the
H G other triangle.

R AAS Two angles and a nonincluded side
of one triangle are congruent to
△RTW ≅ △CGH two angles and side of the other
triangle.
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