Question

which of these is not to be used as a reason in a proof?
select one:
a. definition
b. theorem
c. postulate
d. guess

which of these is not a part of a formal proof?
select one:
a. statements
b. none of these
c. diagram
d. reasons
e. given

Explanation:

For the first question: Definitions, theorems, and postulates are established, verified statements that form the logical basis for proofs. A guess is an unsubstantiated assumption with no logical rigor, so it cannot be used as a proof reason.
For the second question: A formal proof requires given information, sequential statements that build the argument, and corresponding reasons for each statement. While a diagram can aid understanding, it is not a required, formal component of the proof structure, making it the correct choice.

Answer:

1. d. guess
2. c. diagram