Question

in the diagram, dg || ef. what additional information would prove that defg is an isosceles trapezoid? ef ≅ gf, de ≅ dg, ef ≅ dg, de ≅ gf

Explanation:

An isosceles trapezoid has one pair of parallel sides (bases) and congruent non-parallel sides (legs). Given $\overline{DG} \parallel \overline{EF}$ (bases), the legs are $\overline{DE}$ and $\overline{FG}$. For DEFG to be isosceles, the legs must be congruent.

Answer:

$\overline{DE} \cong \overline{GF}$