Which biconditional is not a good definition

A: an angle is obtuse if and only if the measure is greater than 180

B: an angle is a right angle if and only if it’s measure is 90

C: an angle is acute if and only if it’s measure is between 0 and 90

D: two angles are congruent if and only if their measures are the same

1 answer

Option A: an angle is obtuse if and only if the measure is greater than 180.