Given a parallelogram ABCD. Complete each statement along with the definition property used.

(i) 
(ii) 
(iii) 
(iv) 
(i) In a parallelogram, opposite sides are equal in length
AD = BC
(ii) In a parallelogram, opposite angles are equal in measure
∠DCB = ∠DAB
(iii) In a parallelogram, diagonals bisect each other
Hence, OC = OA
(iv) In a parallelogram, adjacent angles are supplementary to each other
Hence,
m ∠DAB + m ∠CDA = 180°