What is the radius of a circle,to the nearest $cm$,whose area is equal to the sum of the areas of the three circles of radii $22\, cm$,$19\, cm$,and $8\, cm$ respectively? (in $cm$)

Each side of an equilateral triangle is increased by $1.5 \%$. The percentage increase in its area is......$\%$

The perimeter of a rhombus is $60 \, cm$ and one of its diagonals is $24 \, cm$. The area (in $sq. cm$) of the rhombus is

If the ratio of the areas of two squares is $9: 1$,then the ratio of their perimeters is

$A$ hollow spherical shell is made of a metal of density $4.9 \, g/cm^3$. If its internal and external radii are $10 \, cm$ and $12 \, cm$ respectively,find the weight of the shell. (Take $\pi = 3.1416$) (in $gm$)

The two adjacent sides of a parallelogram are $60 \, m$ and $40 \, m$ and one of the diagonals is $80 \, m$ long. The area of the parallelogram is