The cost of levelling a rectangular ground at $Rs. 1.25$ per $sq. metre$ is $Rs. 900$. If the length of the ground is $30$ $metres$,then the width is? (in $metres$)

$A$ rectangular plot has a concrete path running in the middle of the plot parallel to the breadth of the plot. The rest of the plot is used as a lawn,which has an area of $240 \, m^2$. If the width of the path is $3 \, m$ and the length of the path is greater than its breadth by $2 \, m$,what is the area of the rectangular plot (in $m^2$)?

If the sides of a triangle are doubled,its area

$A$ square field with side $30\, m$ is surrounded by a path of uniform width. If the area of the path is $256\, m^2$,then its width is ........ $m$.

The area of an equilateral triangle is $9 \sqrt{3} \ m^{2}$. The length (in $m$) of the median is

In measuring the sides of a rectangle,one side is taken $5 \%$ in excess,and the other $4 \%$ in deficit. Find the error percent in the area calculated from these measurements. (in $\%$)