Since the congruent operator is ≅ and since AD is congruent to BD, I'm going to assume that you want to prove that AD is congruent to BD. 1. DE is equal to CD by definition since D is the midpoint of CE. 2. AE is equal to BC since opposite sides of a rectangle are equal to each other. 3. Angle AEC is equal to Angle BCE since all angles in a rectangle are right angles and all right angles are equal to each other. 4. Triangles ADE and BDC are congruent to each other because we have SAS congruence for both triangles. 5. AD is congruent to BC since they're corresponding sides of congruent triangles.
