Prove or disprove, that the points of intersection of the adjacent trisectors of the angles of any triangle are the vertices of an equilateral triangle. (In other words, that for any yellow triangle, the green triangle will be equilateral, given that the thinner lines trisect their respective angles.)

(In reply to Hey by Raveen)

See for example
http://mathforum.org/library/drmath/view/51789.html
an interactive applet is at
http://www.cut-the-knot.com/triangle/Morley/MorleyFinal.shtml

Posted by Charlie on 2003-02-10 05:13:56