A tub shaped like a cylinder with a radius of 20 in. and a height of 15 in. is filled to the top with water. Six spherical balls, each with a radius of 6 in., are placed in the tub and they sink. Some water overflows from the tub. This amount equals the combined volume of the spheres. Find both the exact and the approximate amount of water that remains in the tub. For the approximate volume, use 3.14 for π. Exact: __ π in3 Approximate: __ in.