State the Zeroth Law of Thermodynamics.

(N/A) The Zeroth Law of Thermodynamics states that if two systems,$A$ and $B$,are each in thermal equilibrium with a third system,$C$,then systems $A$ and $B$ are also in thermal equilibrium with each other.
Thermal equilibrium means that there is no net flow of heat between the systems when they are in contact,which implies that they must be at the same temperature.