1. Geometry 4-3 Triangle Congruence
Given: Δ ABC ≅ Δ DEF
Methods to prove 2 triangles congruent:
SSS
SAS
ASA
AAS
The corresponding line segments and the corresponding angles are congruent.
The following NEVER prove congruence:
SSA
AAA

2. SAS SSS All 3 sides are ≅ therefore the s are ≅N G L I D E I D E I D E
What you you notice about this triangle? Kids will say sides are diff and angles are diff (then click)
Then state that this type of triangle has a special name, scalene (click)
2 sides and their INCLUDED angle are ≅ therefore the s are ≅
* The angle MUST be between the 2 sides
All 3 sides are ≅
therefore the s are ≅

3. AAS
ASA I D E N G L I D E N G L
2 angles and their NON-INCLUDED side are ≅ therefore the s are ≅
* The side CANNOT be between the 2 angles
2 angles and their INCLUDED side are ≅ therefore the s are ≅
* The side MUST be between the 2 angles

4. 1. 2.
Congruent or NOT
Justification
Congruent or NOT
Justification

5. 3. 4.
Congruent or NOT
Justification
Congruent or NOT
Justification

6. Must be a right triangle
H L
Must be a right triangle
The hypotenuse and leg must be congruent to the hypotenuse and leg of another right triangle Y P O T E N U S E G

7. 7. 8.