![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
A cuboid iron box without a cover, 18 cm long, 15 cm wide and 10 cm high. How much iron sheet does it need to make this iron box
Sheet area with cover
（18×15＋18×10＋15×10）×2
=（270＋180＋150）×2
=1200 square centimeters
There are three cases of not stamping
1200-18 × 15 = 930 square centimeter
1200-18 × 10 = 1020 square centimeter
1200-15 × 10 = 1050 square centimeter
Answer; or
Whoosh. The first answer,
A piece of iron sheet 40 cm in length and 20 cm in width is made into an open iron box (cuboid) with a height of 5 cm. How to make it? What is the largest volume?
The bottom area is 20 * 20 = 400 square centimeter, the height is 5 centimeter, the volume is 400 * 5 = 2000 cubic centimeter
Production method: cut half of 40 * 20 sheet iron to make the bottom, that is 20 * 20. Cut the other half into four 5 * 20 strips to make the side of the uncovered iron box
A rectangular iron box, 25 cm in length, 20 cm in width and 15 cm in height. How many square centimeters of iron sheet do you need to make this iron box?
25 × 20 × 2 + 25 × 15 × 2 + 20 × 15 × 2, = 1000 + 750 + 600, = 2350 (square centimeter); answer: this iron box should be made of at least 2350 square centimeter iron sheet
A cuboid is 4m in length, 3m in width and 2m in height. The largest floor area of the cuboid is () m2
A cuboid is 4m in length, 3m in width and 2m in height. The largest floor area of the cuboid is (12) m2
A number minus 16 times 3, plus 12 divided by 48, get 52, what's the number?
Let this number be X. from the meaning of the question, we can get: (x-16 × 3) + 48 △ 12 = 52, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; x-48 + 4 = 52, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp
The sum of the items of sequence 1 / 3, 1 / 9, 1 / 27,... 1 / 3N,... S = ()
S=a(1)/(1-q)=(1/3)/[1-(1/3)]=1/2
Number rule: 1 / 1, 3 / 2, 7 / 8, 13 / 48, 21 / 384, X / y. how much is y?
y=2304
This paper discusses the solution of inequality (M's square + m) * x > m + 1
Obviously, we need to know the relationship between the coefficient m ^ 2 + m before X and 0
(1) If m ^ 2 + M
Seven eighths is a few tenths
0.875
5x + 4y-2m-1 = 0 2x + 3y-m = 0 the process of solving the equations (the answer is: x = (2m + 3) / 7, y = (m-2) / 7)
The process of solving equations
5x+4y-2m-1=0 （1）
2x+3y-m=0（2）
（1）*2
10x+8y-4m-2=0(3)
(2)*5
10x+15y-5m=0(4)
(4)-(3)
7y-m+2=0
y=(m-2)/7
(1)*3
15x+12y-6m-3=0
(2)*4
8x+12y-4m=0
7x-2m-3=0
x=(2m+3)/7
RELATED INFORMATIONS
- 1. There is a rectangular sheet of iron 40 cm in length and 30 cm in width. Cut out an equal small square at its four corners to make a cuboid uncovered sheet iron box 5 cm in depth (the thickness of welding joint is not included). What is the volume of the box?
- 2. A 40 cm long, 30 cm wide rectangular iron sheet, four corners minus a side length of 5 cm square, make a 5 cm deep uncovered rectangular iron box What's the volume of this iron box The thickness of iron sheet is not included
- 3. Make a 5cm deep uncovered rectangular iron box with a 40cm long and 20cm wide rectangular iron sheet. What is the maximum volume of this iron box
- 4. The volume of a cuboid is 192 square centimeters, the bottom is a square with side length of 8 centimeters, and the surface area of the cuboid is ()
- 5. The bottom of a cuboid is a square. Unfold the side of the cuboid and it is a square with side length of 8 cm. Calculate the volume of the cuboid
- 6. A horizontal cuboid with a side length of 8 cm and a height of 3.5 cm is on the bottom. What is the surface area and volume of the cuboid?
- 7. A cuboid with a square bottom is 8 cm high. If its height is increased by 1 / 3, its surface area will be increased by 24 square cm（ emergency
- 8. It is known that the volume of a spherical iron block is measured by a rectangular container with a side length of 8 cm and a height of 16 cm It is known that a rectangular container with a side length of 8 cm on its bottom and a height of 16 cm is used to measure the thickness of the container Measure the volume of a spherical iron block. The water in the container is 2 cm away from the mouth of the cup In the container, some water overflows. When the iron block is taken out, the water surface drops by 5cm Product
- 9. There is a cuboid glass container. The container measures 40cm long, 30cm wide and 35cm high from the inside. He injects some water into the container until the water depth is 10cm. Finally, he puts a cube iron block with 20cm edge length into the water and finds that the top of the iron block is still higher than the water surface. So, what is the water depth at this time?
- 10. A cuboid glass jar, measuring from the inside, 50 cm long, 40 cm wide and 20 cm high. Now pour 1 liter of water into the glass jar, and the water depth is 100 cm______ Cm
- 11. Use a 6-decimeter-long, 4-decimeter-wide rectangular sheet iron to make a 8-centimeter-deep cuboid uncovered sheet iron box (the welding joint is ignored). What is the volume of this sheet iron box? A book is 21 cm in length, 15 cm in width and 0.8 cm in thickness. If you give a book cover with 2 cm edges on the top, bottom, left and right sides, how many square centimeters of paper does it take to wrap the book?
- 12. Master Li wants to weld a rectangular iron box without cover with iron sheet (as shown in the picture). How many square decimeters of iron sheet is needed to make this iron box? How many cubic decimeters is the volume of the iron box?
- 13. A cuboid uncovered iron water tank is 0.8 meters long, 0.65 meters wide and 0.6 meters high. How many square meters of iron is needed to make this water tank? If each liter of water weighs 1 kg, how many kg of water can the tank hold at most? (the thickness of iron sheet is ignored)
- 14. A 24 cm long and 8 cm wide rectangular sheet iron, can you cut it into 5 pieces and weld it into a cuboid container with a cube at the bottom? Draw a picture of the scissors. What's the volume of the container?
- 15. A 24 cm long rectangular sheet iron is cut off from the four corners and welded into a box. The volume of the box is 486 cubic centimeters, and the original width of the sheet iron is calculated
- 16. A 24 cm long rectangular iron sheet is welded into a box without a cover by subtracting a small square with a side length of 3 cm from its four corners. The volume of the box is 486 cubic centimeters That's a good answer Take a 24 cm long rectangular iron sheet, subtract the small square with side length of 3 cm from the four corners, and then weld it into a box without cover. The volume of the box is 486 cubic cm. Calculate the volume of the original rectangle
- 17. A 16 cm long and 8 cm wide rectangular sheet iron, can you cut it into five pieces and weld it into a rectangular container with a square bottom? (no waste) draw a sketch and figure out the volume of the container?
- 18. A 16 cm long and 8 cm wide rectangular sheet iron, can you cut it into five pieces and weld it into a rectangular container with a square bottom? (no waste) draw a sketch and figure out the volume of the container?
- 19. With a 80 cm long, 40 cm wide rectangular sheet iron, cut together into a 10 cm deep container without cover, which can be welded What's your volume? Write down all the spelling methods and answers you come up with
- 20. A 48 cm long and 24 cm wide rectangular sheet iron is used to make a 6 cm deep uncovered cuboid container, and the thickness of welding joint and sheet iron is not considered How many welding methods can you find? How to weld the largest volume There are several welding methods, the length, width and height of each is OK