Question

Which biconditional is NOT a good definition?

a. An angle is a right angle if and only if its measure is 90°
b. An angle is acute if and only if its measure is less than 90°
c. Two angles are congruent if and only if its measure are the same.
d. An angle is obtuse if and only if its measure is greater than 180°

Answer 1

The answer is d because an obtuse angle can be anything over 90°

Answer 2

Two angles are congruent if and only if its measure are the same is not a good definition because congruent angles sometimes does not has the same measures.