13. A circular grassy plot 35 m in radius has a path 3.5 m wide running around it on the outside. Find the cost of gravelling the path at 48 per sq. m.
14. A race track is in the form of a ring whose inner circumference is 220 m and outer circumference is 264 m. Find the area of the track.
15. A wire in the shape of a square of side 16.5 cm is cut and bent in the shape of a circle. What is the difference in the areas of these two figures? 74-25 cm² aree of cirche minu U​