Answer:
the triangles are similar
12/9 = 20/15 = 16 / DE = 1.3333
k = 1.3333 (k is the similarity coefficient.)
16 / DE = 1.3333
DE = 12
the perimeter of CDE = 15 + 9 + 12 = 36
the ratio of the areas of two similar triangles is equal to the square of the coefficient of their similarity
96 / area CDE = 1.333^2
area CDE = 54