**Geometry Chapter 4.3 Triangle are Congruent by SSS and SAS**

**I) Postulates**:

**SSS = SSS Congruence Postulate**- if three sides of one triangle are congruent to three sides of a second triangle, then the two triangles are congruent.

**Example**: Given ΔABC and ΔDEF,

if AB = DE, BC = EF and AC = DF, then ΔABC = ΔDEF.

**SAS = SAS Congruence Postulate**- if two sides and the included angle of one triangle are congruent to two sides and the included angle of a second triangle, then the two triangles are congruent.

**Example**: Given ΔABC and ΔDEF,

if AB = DE, BC = EF and ∠B = ∠E, then ΔABC = ΔDEF.

**Geometry Chapter 4.4 Triangles are Congruent by ASA and AAS**

**II) Postulates:**

**ASA = ASA Congruence Postulate**- if two angles and the included side of one triangle are congruent to two angles and the included side of a second triangle, then the two triangles are congruent.

**Example**: Given ΔABC and ΔDEF,

if angle A = angle D, AB = DE, and angle B = angle E, then Δ ABC = Δ DEF.

**AAS = AAS Congruence Postulate**- if two angles and a nonincluded side of one triangle are congruent to two angles and the corresponding nonincluded side of a second triangle, then the two triangles are congruent.

**Example**: Given Δ ABC and Δ DEF,

if angle A = angle D, angle C = angle F, and BC = EF , then Δ ABC = Δ DEF.