The polynomial function defined by f (x )equals StartFraction pi Over 3 EndFraction x cubed minus 10 pi x squared plus StartFraction 4000 pi d Over 3 EndFraction can be used to find the depth that a ball 20 cm in diameter sinks in water. The constant d is the density of the ball, where the density of water is 1. The smallest positive zero of f(x) equals the depth that the ball sinks. Approximate this depth for each material and interpret the results. a) A wooden ball with d equals 0.8 . b) A solid aluminum ball with d equals 2.7 . c) A spherical water balloon with d equals 1.