A square $ABCD$ is inscribed in a circle of radius $10 \mathrm{units}$. Find the area of the circle not included in the square. (Use $\mathrm{\pi }=3.14$)

Find the area of the segment $APB$ shown in figure, if radius of the circle is $21 \mathrm{cm}$ and $\angle AOB=120°$.

$ABCD$ is a square park divided into four equal square parks as shown in figure. Semicircular flower beds are made by the shaded region. The area of shaded region is $k m^2$.  Write the value of $k$.

A memento is made as shown in the fig. Its base $PBCR$ is silver plated from the front side at the rate of $₹2$ per ${\mathrm{cm}}^2$. Find the total cost of silver painting the base $PBCR$ if $ABC$ is an equilateral triangle with side $16 \mathrm{cm}$. (Take $\mathrm{\pi }=\frac{22}{7}$ and $\sqrt{3}=1.73$)

The area of an equilateral triangle is $100\sqrt{3} {\mathrm{cm}}^2$. Taking each vertex as centre of a circle which is described with radius equal to half the length of the side of the triangle [see fig.]. The area of that part of the triangle which is not include in the circles is $k c{m}^2$. Take $\mathrm{\pi }=3.14$ and $\sqrt{3}=1.732$. Write the value of $k$.

$ABCD$ is a rectangle in which $AB:BC=2:1$. $M$ is midpoint of $AB$. $MD$ and $MC$ are one fourth of the circles with centres at $A$ and $B$ respectively. Find the ratio of the area of the rectangle $ABCD$ and the shaded portion.