A trapezium ABCD (with AB∥CD and AD=BC) is inscribed in a circle. The diagonals AC and BD intersect at E. It is given that AB=10cm, CD=6cm and BE=4cm.
(i) Prove that △AEB∼△CED.
(ii) Using part (i), show that AE×EC=BE×ED.
(iii) Establish that ∠AED=∠ABD.
(iv) Calculate the length of ED.