Download Section 4-2

Section 4-2
Some Ways to Prove Triangles Congruent
Postulates:
1. SSS Postulate (Side-Side-Side)
 If three sides of one triangle are congruent to three sides
of another triangle, then the triangles are congruent.
Ex:
D
C
F
A
B
ABC 
By SSS Postulate,
E
DEF
2. SAS Postulate (Side-Angle-Side)
 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.
Ex:
D
By SAS Postulate,
B
A
C
ABD 
CDB
3.
ASA Postulate (Angle-Side-Angle)
 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.
D
B
C
E
A
By ASA Postulate,
ACB 
DCE