Zeroth law of thermodynamics

Zeroth law of thermodynamics states that if two systems A and B are in thermal equilibrium with a third system C separately (that is A and C are in thermal equilibrium; B and C are in thermal equilibrium) then A and B are in thermal equilibrium themselves.

Let us say Ta, Tb and Tc are the temperatures of A, B and C respectively.

A and C are in thermal equilibrium. Ta = Tc

B and C are in thermal equilibrium. Tb = Tc

zeroth-law