In the adjoining figure, show that ABCD is a parallelogram.

Calculate the area of ‖gm ABCD.

In the given figure consider ABD and BCD

Area of ABD = x base x height = x AB x BD

= x 5 x 7 = -------- 1

Area of BCD = x base x height = x DC x DB

= x 5 x 7 = ----------2

From 1 and 2 we can tell that area of two triangle that is ABD and BCD are equal

Since the diagonal BD divides ABCD into two triangles of equal area and opp sides AB = DC

ABCD is a parallelogram

Area of parallelogram ABCD = Area of ABD + Area of BCD

= = cm² = 35 cm²

Area of parallelogram ABCD = 35cm²