Answer :
1. [tex]\overline{DB}[/tex] is perpendicular to [tex]\overline{AE}[/tex] at [tex]C[/tex] (given)
2. [tex]\angle ACB[/tex] and [tex]\angle DCB[/tex] are right angles (perpendicular lines form right angles)
3. [tex]\triangle ACB[/tex] and [tex]\triangle DCE[/tex] are right triangles (a triangle with a right angle is a right triangle)
4. [tex]C[/tex] is the midpoint of [tex]\overline{AE}[/tex] (given)
5. [tex]\overline{AC} \cong \overline{CE}[/tex] (definition of midpoint)
6. [tex]\overline{AB} \cong \overline{DE}[/tex] (given)
7. [tex]\triangle ACB \cong \triangle ECB[/tex] (HL)
8. [tex]\angle BAC \cong \angle DEC[/tex] (CPCTC)
9. [tex]\overline{DE} \parallel \overline{AB}[/tex] (converse of alternate interior angles theorem)