the complete question in the attached figure
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°.
m angle bcd=∠C=180-∠B=180°-105°=75°
the answer is m angle bcd=75°