The area of a trapezium is $2500 \, m^2$. One of its parallel sides is $75 \, m$. If the distance between the two parallel sides is $40 \, m$,then find the length of the other parallel side in $m$.

In trapezium $ABCD$,$AB || CD$ and $AB = 2 \, CD$. Its diagonals intersect at $O$. If the area of $\Delta AOB = 84 \, cm^2$,then the area of $\Delta COD$ is equal to (in $cm^2$)

If the perimeter of an isosceles right triangle is $(6+3 \sqrt{2}) \text{ m}$,then the area of the triangle is ... $\text{m}^2$.

$A$ rectangular park $60 \, m$ long and $40 \, m$ wide has two concrete crossroads running in the middle of the park, and the rest of the park has been used as a lawn. If the area of the lawn is $2109 \, m^2$, then what is the width of the road? (in $m$)

$A$ field is in the shape of a parallelogram. Its adjacent sides and one diagonal are $65 \, m$,$119 \, m$,and $156 \, m$ respectively. Find the cost of gravelling it at the rate of $₹ 10$ per $m^2$ (in $Rs.$).

What will be the area of a semi-$circle$ whose perimeter is $36 \, cm$? (in $cm^2$)