Final answer:
The rule describing the transition PQR=PQR is the Reflexive Property, indicating that any geometric figure, number, or expression is equal to itself.
Step-by-step explanation:
The rule describing the transition PQR=PQR is the Reflexive Property. This property, in the context of geometry or algebra, states that any geometric figure, number, or expression is equal to itself. It's a fundamental principle that's often used implicitly in proofs and equations.
For instance, in the context of a triangle, this property would mean that triangle PQR is congruent to itself, which is a logical statement indicating that every geometric figure is identical to itself.
In contrast to some other properties which might be less intuitive, the reflexive property's foundational nature is widely accepted and doesn't usually need to be proven within mathematical arguments, as it's considered a given.