Question

The figure ABCD is a quadrilateral in which AB = CD and BC = AD. Find its area.

Answer 1

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 $\Delta ABC=\frac{1}{2}\times Base\times Height$
$=\frac{1}{2}\times 12\times 3$
$=18c{m}^2$
$\therefore$ Area of the parallelogram $ABCD=2\times Areaof\Delta ABC$
$=2\times 18$
$=36c{m}^2$