Answer:
∠ CAD = 83°
Explanation:
In a parallelogram. opposite angles are congruent.
∠ CAB = ∠ ACD = 57° ( Alternate angles )
The sum of the 4 interior angles = 360°
and
∠ ABC + ∠ CDA = 40° + 40° = 80°
Thus
∠ BCD + ∠ CAD = 360° - 80° = 280°, then
∠ DAB = 140° ( congruent opposite angles )
Thus
∠ CAD = 140° - ∠ CAB = 140° - 57° = 83°