It seems to be the case that if \(AB=BC=CD\) and \(\angle ABC+\angle BCD = 240^{\circ}\), then the angle bisectors of \(\angle ABC\) and \(\angle BCD\) intersect on \(\overline{AD}\). Can someone prove or disprove this?

Edit: I forgot to mention that ABCD must be a quadrilateral.

Unavailable Dec 18, 2018

edited by
Guest
Dec 18, 2018

#1**0 **

I am going to try to draw a diagram, but I am not 100% sure if it is the correct shape. Usually, for geometry, we prove things correct, unless it is an indirect proof, then we prove the conclusion wrong and work towards the true conclusion.

PartialMathematician Dec 18, 2018