A brooch is made with silver wire in the form of a circle with diameter $35 \mathrm{m}\mathrm{m}.$ The wire is also used in making$5$diameters which divide the circle into $10$equal sectors as shown in figure. Find the total length of the silver wire required.

In the adjoining figure, $AB \text{and} CD$ are respectively arcs of two concentric circles with centre $O$ of a radii $7 \mathrm{cm} \text{and} 3.5 \mathrm{cm}$. If $\angle AOB = 30°$, find the area of the shaded region.

In the adjoining figure, two concentric circles with centre O have radii 21 cm and 42 cm. If ZAOB = 60°, find the area of the shaded region.

A calf is tied with a rope of length 6 m at the corner of a square grassy lawn of side 20 m. If the length of the rope is increased by 5.5 m, find the increase in area of the grassy lawn in which the calf can graze.

In figure, arcs have been down of radius $21 \mathrm{cm}$ each with vertices $A, B, C$ and $D$ of quadrilateral $ABCD$ as centres. Find the area of the shaded region. 

A chord of a circle of radius $14 \mathrm{cm}$ subtends an angle of $60$ at the centre. Find the area of the corresponding minor segment of the circle. $\left[\text{Use} \mathrm{\pi }=\frac{22}{7} \text{and} \sqrt{3}=1.73\right]$

In a circle of radius $21 \mathrm{cm}$, an arc subtends an angle of $60°$ at the centre. Find the length of the arc.

In a circle of radius $21 \mathrm{cm}$, an arc subtends an angle of $60°$ at the centre. Find the area of the sector formed by the arc.