A proof uses postulates and theorems to prove some statement.
It is a consequence of Euclid's parallel postulate. In fact, in some versions, the statement that "a plane triangle has interior angles that sum to 180 degrees" replaces the parallel postulate.
Could you please specify which postulate you are referring to?
There are many kinds of statement that are not theorems: A statement can be an axiom, that is, something that is assumed to be true without proof. It is usually self-evident, but like Euclid's parallel postulate, need not be. A statement need not be true in all circumstances - for example, A*B = B*A (commutativity) is not necessarily true for matrix multiplication. A statement can be false. A statement can be self-contradictory for example, "This statement is false".
When a postulate has been proven it becomes a theorem.
No. A postulate need not be true.
False...A postulate is a statement that does not require proof! P.S.: I know this is late, but I hope it helps!
Postulate
A Postulate
A postulate or axiom is an accepted statement of fact.
postulate
A postulate
if
A postulate or axiom
postulate
theorem
A good postulate is a statement which appears to be true, and perhaps can be shown to be true in simple cases, but which has not yet been proven.