If `triangleABC ~ triangleFED," then "(AB)/(-)=(-)/(ED)`.

Answer

To solve the problem, we need to establish the relationship between the sides of the two similar triangles, triangle ABC and triangle FED.

### Step-by-Step Solution:

1. **Identify the Similar Triangles**:
We know that triangle ABC is similar to triangle FED. This means that the corresponding sides of these triangles are in proportion.

2. **Write the Proportionality Statement**:
Since the triangles are similar, we can write the following ratios based on their corresponding sides:
\[ \frac{AB}{FE} = \frac{BC}{ED} = \frac{AC}{FD} \]

3. **Focus on the Required Ratio**:
We need to express the ratio \( \frac{AB}{?} = \frac{BC}{ED} \). From the proportionality statement, we can see that:
\[ \frac{AB}{FE} = \frac{BC}{ED} \]

4. **Substituting the Known Values**:
From the proportionality, we can rearrange the equation to find the unknown:
\[ \frac{AB}{FE} = \frac{BC}{ED} \]
This means that if we cross-multiply, we get:
\[ AB \cdot ED = BC \cdot FE \]

5. **Final Expression**:
To express \( AB \) in terms of \( ED \) and \( FE \), we can write:
\[ \frac{AB}{FE} = \frac{BC}{ED} \implies AB = \frac{BC \cdot FE}{ED} \]

### Conclusion:
The final proportional relationship we derived is:
\[ \frac{AB}{FE} = \frac{BC}{ED} \]