Cut a cone with a bottom radius of 5cm and a height of 20cm into two cylinders of the same size, and the volume of the two small cylinders is less than that of the cylinder What's the difference between the sum of the surface area and the cylinder before the section?

Cut a cone with a bottom radius of 5cm and a height of 20cm into two cylinders of the same size, and the volume of the two small cylinders is less than that of the cylinder What's the difference between the sum of the surface area and the cylinder before the section?

The sum of the volumes is the same as that of the truncated cylinder
The surface area of the cylinder is 2 * 3.14 * 5 * 5 = 157 square cm larger than that of the original cylinder

The height of a cylinder is 20cm. If the cylinder is cut off 5cm, the surface area of the cylinder is reduced by 31.4cm?

31.4/5=6.28
6.28/3.14=2
3.14/（1*1）=3.14
3.14*5=15.7

The bottom radius of the cylinder is 20 cm, the height is 5 cm, and the surface area is 5 cm?

Bottom area = 3.14 × 20 & # 178; = 1256 (cm2)
Bottom circumference = 3.14 × 20 × 2 = 125.6 (CM)
Side area = 125.6 × 5 = 628 (cm2)
Surface area = 628 + 1256 × 2 = 3140 (cm2)

When its height h = 12.5cm, the bottom area s = 20cm ^ 2
1. Find the functional relationship between S and H
2. Bottom area when height h = 5cm

Function relation: v = h * s, where V = 12.5 * 20 = 250cm ^ 3. It can be said that h and s are inverse proportional functions
h=5cm,S=250/5=50cm^2