The volume of the submerged sphere equals the volume of the displaced water, which is calculated using the formula for the volume of a sphere, V = (4/3) * pi * r^3. Substituting the radius of 6 cm gives a volume of (4/3) * pi * 6^3, which equals 288 * pi cubic centimeters. This volume is spread across the circular base of the cylindrical vessel with radius 8 cm, forming a cylindrical column of water whose height is found using V = pi * R^2 * h. Setting 288 * pi = pi * 8^2 * h yields 288 = 64h, so the rise in water level h is 4.5 cm.