Let
be a convex quadrilateral and draw regular triangles
, the first two outward and the other two inward. Prove that
. What can be said about the quadrilateral
?
%V0
Let $ABCD$ be a convex quadrilateral and draw regular triangles $ABM, CDP, BCN, ADQ$, the first two outward and the other two inward. Prove that $MN = AC$. What can be said about the quadrilateral $MNPQ$?