If the diagonal of a square is doubled to make another square,the area of the new square will

The area of a rectangle is thrice that of a square. The length of the rectangle is $20\,cm$ and the breadth of the rectangle is $\frac{3}{2}$ times that of the side of the square. The side of the square (in $cm$) is

The length of one pair of opposite sides of a square is increased by $5 \, cm$ on each side,the ratio of the length and the breadth of the newly formed rectangle becomes $3:2$. What is the area of the original square? (in $cm^2$)

In a swimming pool measuring $90\, m$ by $40\, m$,$150$ men take a dip. If the average displacement of water by a man is $8\, m^3$,what will be the rise in water level? (in $cm$)

$A$ cylindrical vessel of height $5\, cm$ and radius $4\, cm$ is completely filled with sand. When this sand is poured out,it forms a right circular cone of radius $6\, cm$. What will be the height of this cone? (in $cm$)

In the given figure,$PQR$ is a triangle and quadrilateral $ABCD$ is inscribed in it. Given $QD = 2 \text{ cm}$,$QC = 5 \text{ cm}$,$CR = 3 \text{ cm}$,$BR = 4 \text{ cm}$,and $PB = 6 \text{ cm}$. What is the area (in $\text{cm}^2$) of the quadrilateral $ABCD$?