Which biconditional is NOT a good definition?

A. Two line segments are congruent if and only if they have same length.

B. Two lines are parallel if and only if they do not intersect.

C. Three points are collinear if and only if they lie on the same line.

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

Question

Which biconditional is NOT a good definition?
 
A.	Two line segments are congruent if and only if they have same length.
 
B.	Two lines are parallel if and only if they do not intersect.
 
C.	Three points are collinear if and only if they lie on the same line.
 
D.	A whole number is even if and only if it is divisible by 2

anonymous · Answer

@tcarroll010

anonymous · Answer

That last one is not so good.  Odd numbers are divisible by 2.  They just don't produce integers.