Question

Which biconditional is NOT a good definition?
A. Two angles are supplementary if and only if the sum of their angles measures 180.

B. Two angles are vertical angles if and only if they are nonadjacent and are formed by two intersecting lines.

C. Two angles form a linear pair if and only if the angles are adjacent.

D. The sum of the two angles is 90 if and only if they are complementary.

Answer 1

I think it's c.