From the statement, we know that:
[tex]m\angle ABC=110^{\circ}\text{.}[/tex]
If we extend the segments AD and BC, we have:
From the picture, we see that:
1) The angle m∠SBA is the complement angle of m∠ABC, so we have:
[tex]\begin{gathered} m\angle\text{SBA + m}\angle ABC=180^{\circ}, \\ m\angle\text{SBA }=180^{\circ}-\text{ m }\angle ABC, \\ m\angle\text{SBA = }180^{\circ}-110^{\circ}=70^{\circ}. \end{gathered}[/tex]
2) m∠SBA and m∠WAZ are congruent angles, so we have:
[tex]m\angle WAZ=m\angle SBA=70^{\circ}\text{.}[/tex]
3) Finally because m∠WAZ and m∠BAD are opposite angles, they must be equal:
[tex]m\angle\text{BAD}=70^{\circ}\text{.}[/tex]
Answer
m∠BAD = 70°
