When the diagonals of a quadrilateral intersect at point \( O \) such that \( AO \cdot DO = BO \cdot CO \), this condition is satisfied by a trapezium. This property is characteristic of a trapezium where the diagonals divide each other proportionally.
The correct option is (C): trapezium
Let ABCD be a quadrilateral. If E and F are the mid points of the diagonals AC and BD respectively and $ (\vec{AB}-\vec{BC})+(\vec{AD}-\vec{DC})=k \vec{FE} $, then k is equal to