If a wire is bent into the shape of a square,then the area of the square is $81 \, cm^2$. When the wire is bent into a semi-circular shape,the area of the semi-circle will be (in $cm^2$):

The length of a rectangle is $3/5$ of the side of a square. The radius of a circle is equal to the side of the square. The circumference of the circle is $132 \, cm$. What is the area of the rectangle if the breadth of the rectangle is $8 \, cm$? (in $cm^2$)

The area of the floor of a rectangular hall of length $40\, m$ is $960\, m^{2}$. Carpets of size $6\, m \times 4\, m$ are available. How many carpets are required to cover the hall?

In measuring the sides of a rectangle,one side is taken $5 \%$ in excess,and the other $4 \%$ in deficit. Find the error percent in the area calculated from these measurements. (in $\%$)

The diagonals of a rhombus are $12 \ cm$ and $16 \ cm$. The length of one side is.......$cm$

$A$ square is inscribed in a circle whose radius is $4\, cm$. The area of the portion between the circle and the square is