Final answer:
The question discusses the principle of triangle congruency in geometry, which is used to determine if two triangles are congruent by comparing their sides and angles according to congruency postulates.
Step-by-step explanation:
The question revolves around the concept of triangle congruency, which is a fundamental topic in geometry, a branch of mathematics. Triangle congruency theorems such as SAS (Side-Angle-Side), ASA (Angle-Side-Angle), SSS (Side-Side-Side), and AAS (Angle-Angle-Side) are used to prove that two triangles are congruent, meaning they have the same size and shape. This involves showing that specific pairs of sides and angles are equal between the two triangles in question. To illustrate, if triangles NOF and B₁ A₁ F have corresponding sides and angles that can be matched following one of these postulates, they would be considered congruent.