The length of a rectangular field is twice its breadth. If the rent of the field at ₹ $3500$ per hectare is ₹ $28000$,then find the cost of surrounding it with a fence at ₹ $5$ per meter (in ₹).

$A$ man walked diagonally across a square plot. Approximately what was the percent saved by not walking along the edges?

$A$ 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 $gm$)

$A$ room is $7 \text{ m}$ long and $5 \text{ m}$ broad. The doors and windows occupy $5 \text{ m}^2$. The cost of papering the remaining part of the walls with paper $75 \text{ cm}$ wide,at ₹ $4.20$ per piece of $13 \text{ m}$ length,is ₹ $39.20$. Find the height of the room in $\text{cm}$.

If the length and breadth of a rectangular plot are increased by $50 \%$ and $20 \%$ respectively,then the new area is how many times the original area?

If the diagonals of a rhombus are $8$ and $6,$ then the square of its side is