Answer :
Since DG = EG, this is an isosceles triangle [2 sides of equal length].
Also,
GF bisects the side GE.
That means
EF is half of DE.
Given,
DE = 20.8
EF would be half of 20.8, so
[tex]\begin{gathered} EF=\frac{20.8}{2}=10.4 \\ EF=10.4 \end{gathered}[/tex]Thus,
EF = 10.4