17: 21

**Explanation:**

We known that ratio of areas of two similar triangles is equal to the ratio of square of their corresponding heights.

$$\displaystyle \dfrac{ar(â–³ABC)}{ar . (â–³DEF)}$ = $\displaystyle \dfrac{(4)Â²}{(9)Â²}$ =Â $\displaystyle \dfrac{16}{81}$ â€‹$