The figure ABCD is a quadrilateral in which AB = CD and BC = AD. Its area is
it is clear from the figure that, quadrilateral ABCD is a parallelogram. The diagonal AC of the given parallelogram ABCD divides it into two triangles of equal areas.
Area of the triangle ABC = 
× base × height
= 
× 12 × 3
= 18
Area of parallelogram ABCD = 2 × 18 = 36 cm2
16