Answer: Transitive property of congruence.
Explanation:
Transitive property of congruence is similar to transitive property of equality , it says that if a is congruent to b and b is congruent to c , then a is congruent to c.
Given statement : If AB is congruent to CD and CD is congruent to EF, then AB is congruent to EF.
Here a= AB , b= CD and c= EF
Therefore, the geometric postulates justifies given the statement must be Transitive property of congruence.