In the diagram below, AC is the diameter of the circle AECFG with centre O and BD is a tangent to the circle at C. (ii) Prove that DFEB is a cyclic quadrilateral. (the first part links to this question - it involved me proving that angle FEC = angle FCD).

http://www.mathhelpforum.com/math-he...-untitled1.bmp

Could someone please please give me a hint on how to start this proof???