An arc of a circle whose radius is 21 cm subtends an angle of measure 120 at the centre. Find the length of the arc and area of the sector.

The radius of a circular ground is 63 m. There is 7 m wide road inside the ground as shown in figure 13.10. The blue coloured portion of the road, shown in figure 13.10 is to be repaired. If the rate of repair work of the road costs Rs. 25 per m2, find the total cost of repair.

A regular hexagon of side 10 cm is cut from a plane circular sheet of radius 10 cm as shown in the figure 13.11. Find the area of the remaining part of the sheet. ( = 1.73) (= 3.14)

The length of a minute hand of a circular dial is 10 cm. Find the area of the sector formed by the present position and the position after five minute of the minute hand. (π = 3.14)

The radius of a field in the form of a sector is 21 m. The cost of constructing a wall around the field is Rs. 1875 at the rate of Rs. 25 per meter. If it costs Rs. 10 per m2 to till the field, what will be the cost of tilling the whole field?