Why is Axiom 5, in the list of Euclid’s axioms, considered a ‘universal truth’?

Axiom 5: The whole is always greater than the part.

Let us take an example of the cake. When it is whole it will measure 3 pounds but when we took out a part from it and measure its weight then it would come out less than the previous one. Hence, the fifth axiom of Euclid is true for all the universal things. That is the reason that it is considered as a ‘universal truth’.