Can a quadrilateral ABCD be a parallelogram if
(i) ∠D + ∠B = 180° ?
(ii) AB = DC = 8 cm, AD = 4 cm and BC = 4.4 cm
(iii) ∠A = 70° and ∠C = 65°?
(i) If in a quadrilateral ABCD, ∠D + ∠B = 180°, then it is not necessary that ABCD is a parallelogram.
(ii) Since AD ≠ BC, i.e., the opposite sides are unequal, so ABCD is not a parallelogram.
(iii) Since ∠A ≠ ∠C, i.e., the opposite angles are unequal, so ABCD is not a parallelogram.