In △ABC, ∠B=90∘. The perpendicular from B to the hypotenuse AC meets AC at D. Given that AB=6cm and BC=8cm, answer the following:
(i) Prove that △ADB∼△ABC.
(ii) Using the result of part (i), show that AD⋅AC=AB2.
(iii) Hence find the length of AD.
(iv) Calculate the length of the altitude BD.