Hello. The key to solve the problem lies in the volume of the cone. "After the cone sinks into the water, the water surface rises for 3 minutes" means that the volume of the cone should be the bottom area of the cylinder × the rising height. Then use the volume of the cone x the area of the bottom, and it will be high. Step-by-step formula: 4× 4× π× 3 = 150.72 (cubic decimeter) This is the volume of the cone. 2× 2× π = 12.56 (square decimeter) This is the bottom area of the cone. 150.72× 3 ÷12.56 = 36 (decimeter) The formula for finding the height of the cone is H = 3v ÷ s, so 36 is the height of the cone. Comprehensive formula: [(4×4×π×3)×3]÷2×2×π)= 36 (decimeter). The key to solving the problem is not to be disturbed by too much information, such as the height of the cylinder and the bottom area of the cylinder, which are all disturbing information and can be ignored. Another point is to be familiar with the volume formula. π in the formula should be changed to 3. 14. I hope my answer can help you and be adopted.