Is this it?

In a cylindrical container with a diameter of 20 cm, a conical iron block with a bottom radius of 3 cm was placed and completely immersed in water, and the water level rose by 0.3 cm. The height of the conical iron block is () cm?

The answer is 10.

Because the cone is completely submerged in the water, the volume of the cone can be obtained as v = ∏ (d/2) 2 * ⊿ h = ∏ * (20/2) 2 * 0.3 = 30 ∏ according to the rise of the water surface by 0.3 cm.

The volume of the cone is equal to1/3 * ∏ * R2 * h =1/3 * ∏ * 3 2 * h = 3 ∏ h = 30 ∏, thus obtaining h= 10.