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 $cm^2$)

The length of a rectangular plot of ground is four times its breadth and its area is $4$ hectares. How long will it take for a dog to walk around it at the rate of $3\, km/hr$? (in $min$)

If the perimeter of a rectangular field is $200\, m$ and its breadth is $40\, m$,then its area is (in $m^2$):

There are two squares $s_{1}$ and $s_{2}$. The ratio of their areas is $4:25$. If the side of $s_{1}$ is $6 \text{ cm}$,what is the side of $s_{2}$? (in $\text{cm}$)

The area of a field in the shape of a trapezium is $1440 \, m^2$. The perpendicular distance between its parallel sides is $24 \, m$. If the ratio of the parallel sides is $5:3$, the length of the larger parallel side is ....... $m$.

If the length and breadth of a rectangular room are each increased by $1\, m$,then the area of the floor is increased by $21\, m^2$. If the length is increased by $1\, m$ and the breadth is decreased by $1\, m$,then the area is decreased by $5\, m^2$. The perimeter of the floor is.......$m$.