Question

James is given the diagram below and asked to prove that angle D = angle F.

What would be the missing step of the proof?

Given: DE = FE, and EO forms the angle bisector of angle DEF.

Prove: Angle D=AngleF

Answer 1

The angle DEF is bisected by EO. Thus, by the angle bisctor following holds.

$\angle\text{DEO}\cong\angle\text{FEO}$

Thus, answer is option D.