We are given that the second figure is a dilation of the first one by 15. Thus, the ratio of their corresponding sides is equal to
C'D'E:CDE = 15:1
For the areas,
A of C'D'E': A of CDE = 225:1
Thus, if we have the area of CDE, we just have to multiply that with 225 to have the area of C'D'E'.