Put the round steel in water 8 cm above the water surface, and the water in the bucket will drop by 4 cm.

Then the volume of round steel exposed to water = 3.14 * (10/2) 2 * 8 = 628 cubic centimeters.

Bottom area of cylindrical bucket =628/4= 157 cm2.

If all round steel is put into the water, the water in the bucket will rise by 9 cm; therefore

Round steel volume

= 157*9

= 14 13 cubic centimeter