Segments DF, DH, and GF are tangent to the circle. Andrew was asked to find DF. Explain andrew's error.

Answer:
DF = 14
Step-by-step explanation:
Andrew was wrong in the assumption that DE = EF
Segments of tangents to a circle from the same external point are congruent
That is
EF = FG = 8
Then
DF = DE + EF = 6 + 8 = 14