In a quadrilateral ABCD, ∠ABC=90∘ and ∠ADC=90∘. It is given that AB=DC and BC=AD.
(i) Prove that △ABC≅△CDA.
(ii) Hence, show that ∠CAD=∠DAB.
(iii) What special name can be given to the line AC with respect to ∠A of the quadrilateral? Justify your answer.