Which expression can be used to find the volume of the sphere? A sphere with radius 9 inches. V = four-thirds pi r squared = four-thirds (3.14) (9) squared V = four-thirds pi r cubed = four-thirds (3.14) (9) cubed V = four-thirds pi r cubed = four-thirds (3.14) (18) cubed V = four-thirds pi r cubed = four-thirds (3.14) (18) cubed