If the radius of a circle is increased by $75 \%,$ then its circumference will increase by (in $\%$)

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?

$A$ rectangular sheet of cardboard is of $4 \, cm \times 2 \, cm$. If a circle of the greatest possible area is cut from it,then the area of the remaining portion is:

Find the area of an isosceles right-angled triangle whose hypotenuse is $8\, cm$.

$A$ silver wire when bent in the form of a square,encloses an area of $484 \, cm^{2}$. Now if the same wire is bent to form a circle,the area enclosed by the circle would be? (in $cm^{2}$)

$A$ wire of length $44 \ cm$ is first bent to form a circle and then rebent to form a square. The difference of the two enclosed areas is ....... $cm^2$.