(i) Yes, ΔABD ≅ ΔACD by RHS congruence condition.
(ii) We have used Hypotenuse AB = Hypotenuse AC
AD = DA
∠ADB = ∠ADC = 90° (AD ⊥ BC at point D)
(iii) Yes, it is true to say that BD = DC (corresponding parts of congruent triangles)
Since we have already proved that the two triangles are congruent.