we know that m angle bad =75° remember that on parallelogram (∠A + ∠B) = 180° [Since, sum of the interior angles on the same side of the transversal is 180°] therefore ∠B=180°-∠A=180°-75°=105° ∠B=105° Similarly ∠B + ∠C = 180° ∠C + ∠D = 180° and ∠D + ∠A = 180° Thus, the sum of any two adjacent angles of a parallelogram is 180°.