Postulates need to be proven

Answer 1

Such statements are called postulates in geometry and axioms in other areas.

Definitions are also accepted without proof, but technically they are abbreviations rather than statements.

Answer 2

Yes, it is true. However, it is possible that the postulate is false. For example, although in plane geometry Euclid's parallel postulate is true, it is not true for alternative geometries.

Answer 3

No. Postulates are assumed to be true, without proof.

Answer 4

Yes, they are.

Answer 5

false