answer: : ∠def ≅ ∠abc when jk is constructed equal to hi. a
the figure shows two triangles bhi and ejk constructed using a compass and a straightedge. from the given construction you can conclude that bh≅bi≅ej≅ek (teo arcs drawn must have the same radii). if hi≅jk, then triangles bhi and ejk are congruent by sss postulate.if two triangles are congruent, then their corresponding sides and corresponding angles are congruent too. this gives you that ∠def≅∠abc.