In △ABC, AB=12cm and AC=18cm. Points D and E are taken on AB and AC respectively such that AD:AB=AE:AC=2:5.
(i) Prove that △ADE∼△ABC.
(ii) Find the lengths AD and AE.
(iii) Determine the ratio of the areas [△ADE]:[△ABC].
(iv) Hence find the area of △ADE if [△ABC]=270cm2.