In a rectangle, if the angle between a diagonal and a side

In a rectangle, if the angle between a diagonal and a side is 30° and the length of diagonal is 6 cm, the area of the rectangle is :

As per given figure , we can see that
Let, ABCD be the rectangle in which ∠BAC = 30° and AC = 6 cm.
In triangle BAC , we have

AB	=	cos30°	=	√3	⇒	AB = 3 √3 cm.
AC				2

BC	=	sin30°	=	1	⇒	BC = 3 cm.
AC				2

∴ Area of the rectangle = Length x Breadth = AB X BC = 9 √3 cm²