Find the area of a square of side $4 \mathrm{cm}$. If the side of the square is doubled, find the area of the resulting new square.

Which of the following has a larger area and by how much?
(i) Rectangle with length $10 \mathrm{cm}$ and breadth $6.28 \mathrm{m}$
(ii) Circle with diameter $4.2 \mathrm{m}$

[Take $\mathrm{\pi }=3.14$]

If the area enclosed between two concentric circles of radii $8 \mathrm{cm}$ and $6 \mathrm{cm}$, respectively is $k {\mathrm{cm}}^2$, find $k$. [Use $\mathrm{\pi }=\frac{22}{7}$]

The side of a rhombus is $10 \mathrm{cm}$ and one of its diagonals is $12 \mathrm{cm}$. Find its perimeter and area.

If the area of the shaded portion in the following figure is $k {\mathrm{cm}}^2$, find $k$ in decimal number. [Take $\mathrm{\pi }=\frac{22}{7}$]