First of all, the area of A is larger than that of B 10 cm2, so the area of B plus ABCD excluding A should be smaller than that of rectangular ABCD 10 cm2, and since AB = 10 cm2 and BC = 6 cm, the area of ABCD is 60 cm2, so the area of triangular CDE is 60-/kloc-0. Because the area of triangle DCE is the base multiplied by the height divided by 2, the base is DC (as long as AB), and CE = 50 * 2/ 10 = 10, so BE = CE-BC = 4cm.

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