In the figure, ABCD is a cyclic quadrilateral, if ∠ BAD = 110°, then ∠ BCD =

55°
140°
70°
110°

We know that the opposite angles of a cyclic quadrilateral are supplementary
∠ BAD + ∠ BCD = 180°,
then ∠ BCD = 180° - 110° = 70°