To cast a cone with a bottom diameter of 40 cm and a height of 15 cm, it is necessary to cut off a cylinder with a bottom diameter of 10 cm

To cast a cone with a bottom diameter of 40 cm and a height of 15 cm, it is necessary to cut off a cylinder with a bottom diameter of 10 cm

What is the volume of the cone part
(40 △ 2) × (40 △ 2) × 3.14 × 15 × 1 / 3 = 6280 cm3
What is the base area of the cylinder steel
(10 △ 2) × (10 △ 2) × 3.14 = 78.5 square centimeter
Cylinder steel length
6280 △ 78.5 = 80cm

Forge a cube steel with an edge length of 4 decimeters into a cylinder with a circumference of 12.56 cm at the bottom, and calculate the length of the cylinder steel. (the number obtained shall be kept to one decimal place)
GG, mm help

The test site is calculated according to the constant volume
Radius = 12.56 / (3.14 * 2) = 2cm
Length = (4 * 4 * 4) / (2 * 2 * 3.14) = 5.1cm
The answer is 5.1 cm

The side view of a cylinder is a square, the side length of the square is 12.56cm, and the volume of the cylinder is______ ．

3.14 × 12.56, = 3.14 × 4 × 12.56, = 157.7536 (cubic centimeter), answer: the volume of this cylinder is 157.7536 cubic centimeter. So the answer is 157.7536 cubic centimeter

Unfold the side wrapping paper of a cylindrical food can to get a square. The bottom radius of the cylindrical can is 5cm, and the height of the cylinder is 5cm______ (expressed in π)

Because the side of the cylinder is square, so the height of the cylinder = the circumference of the bottom, C = 2 π r = 2 × π × 5 = 10 π cm; answer: the height of the cylinder is 10 π cm. So the answer is: 10 π cm