Side Side Side postulate states that if three sides of one triangle are congruent to three sides of another triangle, then these two triangles are congruent.
Example
$$\triangle ABC \cong \triangle XYZ $$
 All 3 sides are congruent
 ZX = CA (side)
 XY = AB (side)
 YZ = BC (side)
 Therefore, by the Side Side Side postulate, the triangles are congruent
Given:$$ AB \cong BC, BD$$ is a median of side AC.
Prove:$$ \triangle ABD \cong \triangle CBD $$

Theorems and Postulates for proving triangles congruent
 Hypotenuse Leg Theorem
 Side Side Side
 Side Angle Side
 Angle Side Angle
 Angle Angle Side
 isosceles triangle proofs
 CPCTC
 indirect proof
 quiz on all theorems/postulates
 Images
 Free Math Printable Worksheets:
 Worksheets & Activities on Triangle Proofs