Which biconditional is NOT a good definition?

A whole number is even if and only if it is divisible by 2.

An angle is straight if and only if its measure is 180.

A ray is a bisector of an angle if and only if it splits the angle into two angles.

A whole number is odd if and only if the number is not divisible by 2.

3 answers

An angle is straight if and only if its measure is 180.
wrong. It should have been C. The correct definition is
A ray is a bisector of an angle if and only if it splits the angle into two congruent angles.
Apologies for the mistake. Thank you for the correction. The correct answer is C.