Given a parallelogram ABCD. Complete each statement along with the definition or property used. (i) AD = ? (ii) ∠DCB = ? (iii) OC = ? (iv) m∠DAB + m∠CDA = ?

(i) AD = BC [Opposite sides are equal in parallelogram]
(ii) ∠DCB = ∠DAB [Opposite angles are equal]
(iii) OC = OA [Diagonals bisect each other]
(iv) m∠DAB + m∠CDA = 180° [Adjacent angles are supplementary]