If the two diagonals of a parallelogram are $72 \, cm$ and $30 \, cm$ respectively,then find its perimeter in $cm$.

$A$ circular wire of length $168 \text{ cm}$ is cut and bent in the form of a rectangle whose sides are in the ratio of $5:7$. What is the length (in $\text{cm}$) of the diagonal of the rectangle?

The surface area of a spherical part of a bowl with a flat circular detachable cover,excluding the cover,is $616 \, cm^2$. The area of the cover is $38.5 \, cm^2$. What is the volume of the bowl? (in $cm^3$)

$A$ circular park has a path of uniform width around it. The difference between the outer and inner circumferences of the circular path is $132 \, m$. Its width is.....$m$.

Four circular cardboard pieces,each of radius $7\, cm$,are placed in such a way that each piece touches two other pieces. The area of the space enclosed by the four pieces is.......$cm^2$.

If every side of a triangle is doubled,the area of the new triangle is $K$ times the area of the old one. $K$ is equal to