A quadrilateral ABCDABCDABCD has sides AB=4,BC=5,CD=6,DA=7AB=4, BC=5, CD=6, DA=7AB=4,BC=5,CD=6,DA=7. If ∠B+∠D=180∘\angle B + \angle D = 180^\circ∠B+∠D=180∘, calculate the area of the quadrilateral.
12\sqrt{6}
6\sqrt{6}
24
18