2006 Seniors Pancyprian/2nd grade/Problem 4

Problem

A quadrilateral $ABCD$, that has no parallel sides, is inscribed in a circle, its sides $DA$, $CB$ meet at $E$ and its sides $BA$, $CD$ meet at $Z$. If the bisectors of of $\angle DEC$ and $\angle CZB$ intersect the sides of the quadrilateral at the points $K , L, M ,N$ prove that

i)The bisectors intersect normally

ii)the points $K , L, M ,N$ are vertices of a rhombus.

Solution


See also