Answer: 80 feet.
Step-by-step explanation:
1. As you can see in the figure, triangle ABC and the triangle DFG are similar.
2. The scale of factor of triangle ABC to triangle DFG is the following:
3. Therefore, the lenght of the side DG of the trinagle DFG is:
4. The perimeter of the triangle DFG is:
5. Therefore, she would need 80 feet of fence.