If the perimeter of an equilateral triangle is $12\, m$,then find its area.

$A$ 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 perimeter of a non-square rhombus is $20 \, cm$. One of its diagonals is $8 \, cm$. The area of the rhombus is.........$cm^2$

The radius of a circular wheel is $1 \frac{3}{4} \text{ m}$. How many revolutions will it make in travelling $11 \text{ km}$?

An oblong piece of ground measures $19$ $meters$ $2.5$ $dm$ by $12$ $meters$ $5$ $dm$. From the centre of each side,a path $2$ $meters$ wide goes across to the centre of the opposite side. Find the cost of paving these paths at the rate of $Rs.$ $12.32$ per $sq$ $meter$. (in $Rs.$)

Inside a square plot,a circular garden is developed which exactly fits in the square plot and the diameter of the garden is equal to the side of the square plot which is $28\, m$. What is the area of the space left out in the square plot after developing the garden? (in $m^2$)