How to calculate the surface area and volume of a half cylinder?

The volume of a semicircle is easy to find. Just calculate the volume of the whole cylinder and divide it by 2
The surface area of a semi-circular cylinder is quite complicated. To calculate the surface area of the whole cylinder, divide it by 2, and then add the area of a rectangular section to get the surface area of a semi-circular cylinder. The area of a rectangular section = the diameter of the cylinder * the height of the cylinder

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1. The volume formula of cone is______ The formula for calculating the volume of a cylinder is______ ．
2. There are five same cylindrical columns in the hall. The perimeter of the bottom surface of each column is 3.14 meters and the height is 4 meters. To paint these columns, 0.5 kg per square meter, how many kg of paint do you need?
3. There are 10 cylindrical columns in the hall of the children's palace. The perimeter of its bottom surface is 1.8 meters, and the height is 6.5 meters. If you use about 650 grams of paint per square meter, you can finish these columns How many kilos of paint does the column need?
4. There are some cylindrical columns on the school playground, one of which has a cross-sectional perimeter of 12.56 decimeters and a height of 4 meters. How many cubic meters is the volume of this column? one
5. A cylindrical column, its bottom circumference is 1.57 meters, 5 meters high, what is the volume of this column?
6. There are four cylindrical concrete columns in the corridor of the newly built experimental building of Yucai primary school. The perimeter of the columns is 1.884 meters and 5 meters Now we need to paint these columns, 0.5 kg per square meter. How many kg of paint do we need To be 100% right, to explain, please
7. There are 10 cylindrical columns in the hall with a perimeter of 1.256 meters and a height of 5 meters. Now they need to be painted. How many square meters is the total area of painting? If 0.8 kg of paint is used per square meter, how much paint is needed to brush these columns?
8. There are 8 columns in a hotel hall. The perimeter of the bottom surface of each column is 25.12dm and the height is 7m. How much does it cost to paint these columns (10.5 yuan per square meter)
9. There are six big cylindrical columns in the lobby of a hotel. The perimeter of the columns is 25.12dm. All of them need to be painted. If the painting fee is 80 yuan per square meter, it will cost more It's due tomorrow. It's a formula
10. Build a cylindrical biogas digester. The perimeter of the bottom surface is 18.84 meters and the depth is 2 meters. Cement the four walls and the bottom surface of the digester. How many square meters is the area of the cement part?
11. A cylinder is 8cm high and 25.12cm in circumference. Now it is cut vertically along its diameter and its surface area is increased______ Square centimeter
12. As shown in the figure, the circumference of the bottom surface of a cylinder is 20cm, the height AB is 4cm, and BC is the diameter of the upper bottom surface. An ant starts from point a, crawls along the side of the cylinder to point C, and the shortest distance is Why is ad half the circumference after unfolding? Isn't ad the diameter of a circle?
13. An ant starts from point a and crawls along the side of the cylinder to point C, Try to find the shortest way to crawl
14. As shown in the figure: the circumference of the bottom surface of a cylinder is 16cm, and the height is 6cm. BC is the diameter of the upper bottom surface. An ant starts from point a and crawls along the side of the cylinder to point C, then the shortest distance for the ant to crawl is______ cm．
15. The circumference of the bottom surface of a cylinder is 18.84 meters, and the height is 1.2 meters
16. 1. The expanded view of the side area of a cylinder is a square. The height of the cylinder is 28.26 cm, so its ground diameter is () cm? 2. Roll a rectangular paper of 16 cm long and 10 cm wide into a cylinder. When the height is 10 cm, the maximum perimeter of the bottom surface is () cm; when the height is 16 cm, the maximum perimeter of the bottom surface is () cm
17. The side area of a cylinder is 94.2 square meters, the height is 1.5 meters, the perimeter of its bottom surface is () meters, and the bottom area is () square meters
18. After the side of a cylinder with a circumference of 6.28 decimeters on the bottom is expanded, a rectangle with a width of 2 decimeters is obtained. What is the side area and volume of the cylinder
19. The side area of a cylinder is 226.08 square decimeters, and the perimeter of its bottom is 37.68 decimeters
20. A cylinder is 12.56 cm high, and its side is expanded to be a square. What is the volume of the cylinder in cubic centimeter