It is given that
[tex]\angle EDF\cong\angle GHF[/tex]
An angle in geometry is denoted by the angle symbol (∠) followed by three letters which represent points that form the angle. ∠EDF means that E and F are the "tips" of the angle and D is the vertex in the middle, therefore, ∠FDE represents the same angle.
[tex]\angle EDF=\angle FDE[/tex]
And also
[tex]\angle GHF=\angle FHG[/tex]
Therefore
[tex]\angle EDF\cong\angle GHF\Rightarrow\angle FDE\cong\angle FHG[/tex]
