20 ÷ 2 = 10 (cm)
Conical volume:
10×10× 3.14×1= 314 (cubic centimeter)
Height of cone:
314× 3 ÷147 ≈ 2.13 (cm)
2. Put a rectangular aluminum block with a length of 30cm, a width of 20cm and a height of 5cm and a conical aluminum block with a bottom circumference of 37.68cm and a height of 30cm. Melted and cast into a cylindrical aluminum block with a bottom radius of 5 cm. What is the height of this cylindrical aluminum block? (Numbers are reserved as integers)
Cuboid volume:
30× 20× 5 = 3000 (cubic centimeter)
Radius of cone:
37.68 ÷ 3. 14 ÷ 2 = 6 (cm)
Conical volume:
6× 6× 3.14×1/3 = 37.68 (cubic centimeter)
Column height:
(3000+37.68) ÷ (5× 5× 3.14) ≈ 39 (cm)
3.( 1) The bottom area of the cone is equal to the bottom area of the cylinder.
(2) The volume ratio of cone to cylinder is 1: 1.
(3) The height of the cone is 4.8 cm. Q: What is the height of the cylinder?
48× 1/3 = 16 (cm)
4. Make a sector with a radius of 15㎝ and a central angle of 120 with cardboard, and enclose this sector into a cone. What is the bottom area of the cone? (er ... just answer this question, what is the bottom area? )
(15× 2× 3.14×120/360)/(3.14× 2) =10 (cm)
10×10× 3.14 = 314 (square centimeter)