Which statement represents the biconditional statement of the conditional statements? if the measures of two angles have a sum of 180º, then the angles are supplements. if two angles are supplements, then their measures have a sum of 180º. a. the measures of two angles have a sum of 180º if and only if the angles are supplements. b. the measures of two angles do not have a sum of 180º if and only if the angles are supplements. c. the measures of two angles do not have a sum of 180º if and only if the angles are not supplements. d. the measures of two angles have a sum of 180º if and only if the angles are not supplements.