17 The diagram shows part of an earring. It is in the shape of a sector of a circle of radius 3 cm and angle 45°, from which a sector of radius 2 cm and angle 45° has been removed. (a) Calculate the shaded area. Give your answer in the form aπ/b , where a and b are integers and as small as possible. (b) The earring is cut from a sheet of silver. The mass of 1 cm^2 of the silver sheet is 1/6 g. By taking the value of π to be 3, estimate the mass of the earring.