8 (a) OAB is a sector of a circle, centre O, radius 6 cm. AOBˆ = 25°. (i) Calculate the length of the arc AB. (ii) Calculate the area of the sector OAB. (b) The sector OAB from part (a) is the cross-section of a slice of cheese. The slice has a height of 5 cm. (i) Calculate the volume of this slice of cheese. (ii) Calculate the total surface area of this slice of cheese. (iii) Another 25° slice of cheese has 3 times the height and twice the radius. Calculate its volume. (c) A dairy produces cylindrical cheeses, each with a volume of 800 cm^3. The height h cm and the radius r cm can vary. (i) Express h in terms of r. (ii) What happens to the height if the radius is doubled?