A cylindrical part with a low surface radius of 1 decimeter and a height of 8 decimeters is fused into a conical part with a low surface radius of 2 decimeters. The height of the conical part is How many?

A cylindrical part with a low surface radius of 1 decimeter and a height of 8 decimeters is fused into a conical part with a low surface radius of 2 decimeters. The height of the conical part is How many?

First, the volume of the cylinder: bottom area: 3.14 × (1 × 1) volume: v = sh
=3.14×1 =3.14×8
=3.14 (square decimeter) = 25.12 (cubic decimeter)
Then calculate the bottom area of the cone: 3.14 × (2 × 2)
=3.14×4
=12.56 (square decimeter)
Because in this problem, the volume of the cylinder = the volume of the cone, so we can directly find out the height of the fused cast cone by using the formula of the height of the cone: H = V cone ﹣ s ﹣ 1 / 3
= 25.12 ÷12.56÷1/3
=2÷1/3
=2×3
=6 (decimeter)
A: the height of conical part is 6 decimeters. We just reviewed it!)