Question A necklace is made by using 10 wooden spheres and 10 wooden cylinders. The radii, r,

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A necklace is made by using 10 wooden spheres and 10 wooden cylinders. The radii, r, of the spheres and the cylinders are exactly the same. The height of each cylinder is h. The wooden spheres and cylinders are to be painted. (Ignore the holes in the spheres and cylinders.) 9.1 9.2 9.3 V = xr²h V=-^r² S=2x r² + 2x rh S=4 nr² If the volume of a cylinder is 6 cm³, write h in terms of r. Show that the total surface area (S) of all the painted surfaces of the necklace is equal to S=60r²+120 Determine the value of r so that the least amount of paint will be used. (1) (4) (4) [9] A necklace is made by using 10 wooden spheres and 10 wooden cylinders. The radii, r, of the spheres and the cylinders are exactly the same. The height of each cylinder is h. The wooden spheres and cylinders are to be painted. (Ignore the holes in the spheres and cylinders.) 9.1 9.2 9.3 V = xr²h V=-^r² S=2x r² + 2x rh S=4 nr² If the volume of a cylinder is 6 cm³, write h in terms of r. Show that the total surface area (S) of all the painted surfaces of the necklace is equal to S=60r²+120 Determine the value of r so that the least amount of paint will be used. (1) (4) (4) [9]