We know that the triangles ∆ABC and ∆FED are congruent. As such, we know that all sides and inner angles are congruent. Moreover, if we have:
Then,
[tex]\begin{gathered} \measuredangle A\cong\measuredangle F \\ \measuredangle B\cong\measuredangle E \\ \measuredangle C\cong\measuredangle D \end{gathered}[/tex]And this means that ∡A≅∡F.