Write the formula for the following :

Area of a rectangle.

Write the formula for the following :

Area of a square.

Write the formula for the following :

Perimeter of a regular polygon.

If the perimeter of the following figure is $k \mathrm{cm},$ then find $k.$

Find the length of a rectangular park, whose area is $140 {\mathrm{cm}}^2$ and breadth is $10 \mathrm{cm}$.

The perimeter of a rectangle is equal to perimeter of a square of area $36 {\mathrm{cm}}^2$. The breadth of the rectangle is $4 \mathrm{cm}$. What is the length and area of the rectangle?

The dimension of a carom board, which is in square shape is given below. Each side of the board is$40 \mathrm{cm}$.There are four square holes in each corner of the board of size $6 \mathrm{cm}\times 6 \mathrm{cm}$. If the area that can be used for playing is $k {\mathrm{cm}}^2$ then find the value of $k$.