Question

1. which of the following should not be used as justification in a formal proof?

postulates
theorems
venn diagrams
axioms

Explanation:

In a formal proof, axioms, postulates, and theorems are used as justifications since they are based on logical or mathematical principles. Venn diagrams are visual tools for illustrating set relationships or logical concepts but do not provide rigorous logical justification in a formal proof structure.

Answer:

B. Venn diagrams