Consecutive angles of a parallelogramare supplementary. So, sum of ∠A and ∠D must be equal to 180°. Therefore,
∠A + ∠D = 180°.
Now ∠D can be break into ∠ADB and ∠ BDC. So,
∠A + ∠ADB + ∠BDC = 180
96 + ∠ADB + 38 = 180
134 + ∠ADB = 180 Combine the like terms.
134 +∠ADB -134 = 180 - 134 By subtracting 134 from each sides.
∠ADB = 46
So, measure of ∠ADB is 46°.
