1. **Stating the problem:**
Given a polygon with points and segments where $EP = FP$, a quadrilateral $ABCD$ with $AC = BD$ and angles $\angle ACD = \angle BDC$, and a trapezoid $ABCD$ with $AB \parallel DC$, $E$ midpoint of $AD$, $BE$ extended to $F$ on $CD$ such that $FE = BE$. We also have $BD = AF$ and $BD \parallel AF$.
2. **Understanding the properties:**
- $EP = FP$ means point $P$ is equidistant from $E$ and $F$.
- $AC = BD$ and $\angle ACD = \angle BDC$ imply congruent triangles or isosceles properties.
- $AB \parallel DC$ defines trapezoid properties.
- $E$ midpoint of $AD$ means $AE = ED$.
- $FE = BE$ and $BD = AF$ with $BD \parallel AF$ suggest parallelogram or congruent segments.
3. **Using the midpoint and parallel lines:**
Since $E$ is midpoint of $AD$, $AE = ED$.
Since $AB \parallel DC$, trapezoid properties apply.
4. **Proving $BD = AF$ and $BD \parallel AF$:**
Given $BD = AF$ and $BD \parallel AF$, quadrilateral $BDAF$ is a parallelogram.
5. **Using $FE = BE$ and $E$ midpoint:**
Since $FE = BE$ and $E$ is midpoint, triangle $BEF$ is isosceles with $BE = FE$.
6. **Conclusion:**
The given conditions establish relationships of equal lengths and parallelism that define congruent triangles and parallelograms within the figures.
Final answer: The conditions confirm $BD = AF$ and $BD \parallel AF$ with $FE = BE$ and $E$ midpoint of $AD$ in the trapezoid with $AB \parallel DC$.
Polygon Segments C519A7
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