4. (5 points) Three identical right trapezoids are positioned as shown in the figure, then $\angle 1=$

 untranslated part: 

(No change needed as there is no additional text to translate.)
$$
\begin{array}{l}
\therefore \angle A B C=\angle E B D=50^{\circ} \\
\text { Also, } \because \angle 1+\angle A B C+30^{\circ}=90^{\circ}, \\
\therefore \angle 1=90^{\circ}-30^{\circ}-50^{\circ}=10^{\circ} .
\end{array}
$$

Therefore, the answer is: $10^{\circ}$.