Find the area of the shaded portion of the square whose side is $20 \mathrm{cm}$.

The area of the shaded path in the following figure is

In the given figure (not drawn to scale), $△\mathrm{ABC}, △\mathrm{EFG}, △\mathrm{KIJ}, △\mathrm{NMO}$ are $4$ different equilateral triangles. Find the perimeter of the figure, if side of the square $\mathrm{PDHL}$ is $8 \mathrm{cm}, \mathrm{AC}=4 \mathrm{cm}, \mathrm{EG}=2 \mathrm{cm}, \mathrm{KI}=3 \mathrm{cm} \text{and} \mathrm{MO}=2 \mathrm{cm}.$

A room is $4 m$ long and $3 m 50 cm$ wide. How many square metres of carpet is needed to cover the floor of the room?

Avneet buys $9$ square paving slabs, each with a side of $\frac{1}{2}$ $\mathrm{m}$. He lays them in the form of a square. Shari does not like his arrangement. She gets him to lay them out like a cross. Which has greater perimeter?