In the figure given below, $PRS, RTQ \text{and} PAQ$ are three semicircles of diameters $10 \mathrm{cm}, 3 \mathrm{cm} \text{and} 7 \mathrm{cm}$ respectively. Find the perimeter of the shaded region. $(\text{Use}=3.14)$ 

Given below, $APB \text{and} CQD$ are semicircles of diameter $7 \mathrm{cm}$ each, while $ARC \text{and} BSD$ are semicircles of diameter $14 \mathrm{cm}$ each. Find the perimeter of the shaded region.

The figure given below shows a kite, in which $BCD$ is in the shape of a quadrant of a circle of radius $42 \mathrm{cm}$. $ABCD$ is a square and $ACEF$ is an isosceles right angled triangle whose equal sides are $6 \mathrm{cm}$ long. Find the area of the shaded region.

In the figure given below, a piece of cardboard, in the shape of a trapezium $ABCD$, and $AB \left|\right| DC$ and $\angle BCD=90º$, quarter circle $BFEC$ is removed. Given $AB=BC=3.5 \mathrm{cm}$ and $DE=2 \mathrm{cm}$. Calculate the area of the remaining piece of the cardboard.

In the figure given below, $ABC$ is a right angled triangle, $\angle B=90°$, $AB=28 \mathrm{cm} \text{and} BC=21 \mathrm{cm}$. With $AC$ as diameter a semicircle is drawn and with $BC$ as radius a quarter circle is drawn. Find the area of the shaded region.

In the figure given below, $ABC$ is a right triangle right angled at $A$. Semicircles are described on $AB, BC \text{and} AC$ as diameters. Find the area of the shaded region.

In the figure given below, $ABC$ is a triangle right angled at $B$ with $AB=14 \mathrm{cm} \text{and} BC=24 \mathrm{cm}$. With vertices $A, B\text{ and} C$ as centres, arcs are drawn, each of radius $7 \mathrm{cm}$. Find the area of the shaded region.

In the figure given below, find the area of the shaded region. $(\text{Use}=3.14)$

Unshaded region consists of a square of side $4 \mathrm{cm}$ and four semicircles of diameter $4 \mathrm{cm}$ each.

In the figure given below, a circle is inscribed in an equilateral triangle $ABC$ of side $12 \mathrm{cm}$. Find the radius of the inscribed circle and the area of the shaded region.