Answer
1. Diameters $\overline{AB}$ and $\overline{CD}$ in Circle E
2. Vertical angles are congruent
3. Congruent angles also share equal measures
4. Measure of central angle is equal to its intercepted arc
5. Congruent central angles have congruent central arcs
6. Arc AC $\cong$ Arc DB
Work Step by Step
1. Given
2. Vertical angles formed by intersecting lines are congruent
3. Definition of congruent angles
4. Definition of a central angle
5. Congruent angles and arcs theorem
