Given a triangle ABC, let D be a point different from A on the external bisectrix ℓ of the angle BAC, and let E be an interior point of the segment AD. Reflect ℓ in the internal bisectrices of the angles BDC and BEC to obtain two lines that meet at some point F. Show that the angles ABD and EBF are congruent. equal anglesgeometryreflectionangle bisector