Final answer:
The reflexive property of congruence proves that a geometric figure, like a line segment BD, is congruent to itself, denoted as BD⋅BD.
Step-by-step explanation:
The property of congruence that would prove BD⋅BD is the reflexive property of congruence. This property states that every geometric figure is congruent to itself. It's a foundational idea in geometry that relates to the concept that an object is always identical to itself; hence, a segment, angle, or other geometric figure has the same size, shape, and measure as itself. This is akin to the reflexive property of equality in algebra, which indicates that a number is always equal to itself (a = a). The reflexive property is used to justify statements of congruence or equality that reflect the same object or value on both sides of the congruence or equality sign.