For a straight cylinder, the perimeter of the side view is 8 π cm. The ratio of the radius of the high and low sides of the cylinder is 2 π: 1. What is the volume of the cylinder?

For a straight cylinder, the perimeter of the side view is 8 π cm. The ratio of the radius of the high and low sides of the cylinder is 2 π: 1. What is the volume of the cylinder?

Side development perimeter = 2 * 2 π R + 2H = 8 π,
h/r=2π
The solution is h = 2 π, r = 1

The volume of a cylinder whose side area is 200 π cm square and the diameter of its bottom is twice of its height

Suppose the high position h of the cylinder, then the diameter is 2H
Then π × 2H × H = 200 π
That is 2 π H & # 178; = 200 π
h²=100
H = 10, the diameter of the bottom is twice the height, that is, the radius of the bottom = the height of the cylinder
So v-cylinder = 3.14 × 10 & # 178; × 10
=3.14×100×10
=3140（cm)³

Calculate the volume and surface area of the following figures (unit: cm)
A cuboid is 12 cm long, 5 cm wide and 6 cm high. Calculate the surface area and volume
A cube is 12 cm long, 12 cm wide and 12 cm high. Calculate the surface area and volume
The diameter of the bottom surface of a cylinder is 6cm long and 25cm high, and the surface area and volume are calculated

Surface area
12 * 5 * 2 + 12 * 6 * 2 + 5 * 6 * 2 = 324 square centimeters
Volume 12 * 5 * 6 = 360 CC
2. Surface area
12 * 12 * 6 = 864 square centimeters
Volume 12 * 12 * 12 = 1728 CC
3. Surface area
6 * 3.14 * 25 + 3.14 * 3 * 3 * 2 = 527.52 square centimeter
Volume 3.14 * 3 * 3 * 25 = 706.5 cm3