Step-by-step explanation:
There may be a more direct way to do this, but here's one way. We make no claim that the statements used here are on your menu of statements.
Statement . . . . Reason
2. ∆ADB, ∆ACB are isosceles . . . . definition of isosceles triangle
3. AD ≅ BD
and ∠CAE ≅ ∠CBE . . . . definition of isosceles triangle
4. ∠CAE = ∠CAD +∠DAE
and ∠CBE = ∠CBD +∠DBE . . . . angle addition postulate
5. ∠CAD +∠DAE ≅ ∠CBD +∠DBE . . . . substitution property of equality
6. ∠CAD +∠DAE ≅ ∠CBD +∠DAE . . . . substitution property of equality
7. ∠CAD ≅ ∠CBD . . . . subtraction property of equality
8. ∆CAD ≅ ∆CBD . . . . SAS congruence postulate
9. ∠ACD ≅ ∠BCD . . . . CPCTC
10. DC bisects ∠ACB . . . . definition of angle bisector