Complete: If $\overline{AE}||\overline{BD}$then $\angle 1\cong$ and$\angle 9\cong$ .

The provided two parallel lines are having two separate lines $\overline{AB}$and $\overline{EB}$that are travelling through them.

The postulate 10 can be used which states that two angles represents the corresponding angles only when a separate line travels through these two lines which are having a parallel relation between them.

The theorem 3-2 can be used which states that if two lines are having a separate line that is traveling through them then the angles are congruent which are positioned on alternate interior side of the lines.

According to the travelling line $\overline{AB}$and postulate 10, the congruent angles are,

$\angle 1\cong \angle 4$

According to the travelling line role="math" localid="1637836897205" $\overline{EB}$and theorem 3-2, the congruent angles are,

According to the obtained congruent angles the first blank should be filled with $\angle 4$and second with $\angle 3$.