Find the cost of laying square grass tiles of side $1.2 \mathrm{m}$ in a rectangular lawn of dimensions $6 \mathrm{m}\times 3.6 \mathrm{m}$ when the cost of one tile is $₹18.$

The floor of a hotel room has dimensions $5.5 \mathrm{m}\times 4 \mathrm{m}$. It is made up of red and white square tiles of side $20 \mathrm{cm}$ as shown in the figure. Find the number of red and white tiles required.

If the area of the figures given below, where each square is of length $1 \mathrm{cm}$, is $k {\mathrm{cm}}^2$, then find the value of $k$.

The length of a rectangle is $\frac{5}{4}\mathrm{th}$ of its breadth. If its perimeter is $81 \mathrm{m}$ and its area is $k {\mathrm{m}}^2$, then find the value of $k$.