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Cut a small square with a side length of 4cm at the four corners of the square iron sheet to make a box without cover, with a surface area of 400cm2. Calculate the side length of the original iron sheet
The surface area of the uncovered box should refer to the area of one side. Equation method: let the bottom side length of the box be x, and the original side length be x + 8, then the bottom area of the box is x ^ 2, and the side area is 4 × x * 4. Column equation: x ^ 2 + 16x-400 = 0, and the solution is: X1 = (- 16 + √ 1856) / 2 = 13.54x2 = (- 16 - √ 1856) / 2 is obviously negative, and the original side length = 13.5
Take a 32 cm long rectangular iron sheet, cut off a small square with a side length of 4 cm around it, and then make a box without a cover. Its volume is 768 cubic cm. How about the width of the original rectangle?
768 △ [(32-4 × 2) × 4] = 768 △ 96 = 8 (CM) 8 + 4 + 4 = 16 (CM) a: the width of this sheet of iron is 16 cm
A square with 5cm side length is cut from four corners of a rectangular sheet iron and folded into a cuboid box without cover, with a volume of 2000cm2. The original sheet iron is long and fast
The bottom of the cuboid is square, with a height of 5 cm;
Bottom area = volume / height = 2000 / 5 = 400 (square centimeter),
Namely:
Side length of square bottom * side length of square bottom = 400 (square centimeter),
Side length of square bottom = 20 (CM), [20 * 20 = 400]
The side length of the original square iron sheet is 20 + 5 + 5 = 30 (CM),
The circumference of the original square iron sheet is 30 * 4 = 120 (CM)
A round grassland, its area is 2826 square meters, what is the diameter of this grassland?
Because 2826 △ 3.14 = 900, 30 × 30 = 900, the radius of the circle is 30 meters, then the diameter of the circle is 30 × 2 = 60 meters. A: the diameter of this grassland is 60 meters
The diameter of a round lawn is 12M, its perimeter is () m, and its floor area is () m2
Perimeter: 12 π, about 37.7m
Area: 36 π, about 113.1 square meters
In a square piece of paper with a circumference of 80 cm, cut the largest circle. The circumference of the circle is [] cm and the area is [] square cm
The length of the square is 20cm. The diameter of the largest circle is 20 and the radius is 10
The area is 100 Π or approximately 314
Cut a piece of 24 decimeter square paper into the largest circle. What is the circumference and area of the circle?
24 △ 4 = 6 (CM), circumference of the circle: 3.14 × 6 = 18.84 (CM), area of the circle: 3.14 × (6 △ 2) 2 = 3.14 × 9 = 28.26 (square cm); answer: circumference of the circle is 18.84 cm, area is 28.26 square cm
A square and a circle have the same perimeter. Given that the perimeter of a circle is 628 meters, what is the area of a square?
Square side length = 628 △ 4 = 157 (m)
Square area = 157 × 157 = 24649 (M2)
The length of a rectangle is reduced by 4cm, and the rest is a square with a perimeter of 24cm. How many centimeters is the perimeter of the original rectangle? How many square centimeters is the area?
Perimeter of square = 4, side length = 24 cm
Side length = 6cm = width of rectangle
The length of a rectangle = width + 4 = 6 + 4 = 10 cm
The original rectangle circumference = 2 (10 + 6) = 32 cm
Area = 10 * 6 = 60 square centimeter
Draw the largest circle in a square with a side length of 10 cm. Its diameter is () cm and its circumference is () cm
If you want to draw the largest circle in a square, you can imagine that only when the four tables of the square are tangent to the circumference
Based on the above principle, then the diameter of the circle will not exceed the perimeter of the square, otherwise it will cross the boundary, so the maximum diameter of the element is 10 cm, and the perimeter is 10 * 3.14 = 31.4 cm
RELATED INFORMATIONS
- 1. A square sheet of iron, four corners cut off four small squares, folded into a bottom side length of 40cm uncovered cuboid box, its volume is 24000cm3______ cm．
- 2. A rectangular cardboard, 10 cm long, 8 cm wide, four corners each cut out a side length of 2 cm square, folded into an open box, its volume A rectangular sheet of iron, 10 cm in length and 8 cm in width, with four corners each cut off, is a square box with a side length of 2 cm [Note: it's a cube! Not a square]. What's the volume of the box? How big is the sheet of iron?
- 3. A 20 cm long, 16 cm wide rectangular sheet iron, four corners of each cut off the length of 4cm small square, make a no cover box. Find the volume of the box It's due tomorrow
- 4. Cut off the square of 10 cm in length at the four corners of a rectangular piece of iron which is twice the length and width, and then fold up the four sides to make a box without a cover His volume is 4000cm square, and the length and width of the rectangular iron sheet are calculated
- 5. There is a rectangular sheet of iron 16 cm wide, which is welded into an open box after subtracting the square with side length of 4 cm from the four corners. The known volume of the box is 76 M & sup3;, what is the original area of this sheet
- 6. There is a rectangular cardboard 8 cm in length and 4 cm in width. A square is cut from each corner and folded into a rectangular paperless box 1 cm in height What is the volume of the box in cubic centimeter?
- 7. The side length of a square cardboard is 1 meter. Cut off the four corners of it by 2 decimeters. Then fold it into an open cardboard box and calculate the volume of the box
- 8. A rectangular iron sheet is welded into a box without cover by subtracting the square with the side length of 4cm from its four corners. The surface area and volume of the box are 20cm wide and 50cm long
- 9. There is a piece of hard paper 20 cm in length and 12 cm in width. Cut a square 2 cm in length at each corner, and then fold it into a cuboid paperless box. The volume of the box is______ Cm
- 10. A cuboid wood is 4m long, 3DM wide and 3DM high. After sawing it into two sections, how many square decimeters has the surface area increased?
- 11. A rectangular sheet of iron, 30 cm long and 25 cm wide. Cut a square with a side length of 5 cm from four corners to make a box. Calculate the volume of the box I'm in a hurry
- 12. It is necessary to prepare () kinds of rectangles of different sizes, the largest of which is 10 cm in length, 8 cm in width and 6 cm in height The largest rectangle area is () square centimeter, and the smallest rectangle area is () square centimeter
- 13. The bottom is a square cuboid carton. Unfold its side to get a square with a side length of 20 cm. How much cardboard does this cuboid carton need at least
- 14. How much cardboard is needed to make 10 rectangular cartons with 81 square centimeter bottom area and 6 centimeter height
- 15. A rectangular cardboard box, 10 cm long, 6 cm wide, 5 cm high, 1 square meter cardboard, how many cardboard boxes can be made? (excluding interfaces)
- 16. A rectangular cardboard box, 10 cm long, 6 cm wide, 5 cm high, has 210 pieces of cardboard of 2 square meters, how many cartons can be made
- 17. A 30 cm long, 20 cm wide rectangular cardboard, cut off the four corners of the small square, you can make a carton without cover, please calculate, how much cubic centimeter is the volume of this carton? What's the surface area?
- 18. A rectangular iron plate is 20 cm long and 14 cm wide. In this way, the cube with a side length of 2 cm is cut off from the four corners, and then it is made into a lidless zygote. What is the volume of this box
- 19. There is a 18cm wide rectangular iron plate. After cutting the square with 4cm side length at the four corners, it is welded into an iron box without feeding. The known volume of the iron box is 760 cubic cm How many square centimeters is the original iron plate area?
- 20. A 30 cm long, 20 cm wide rectangular cardboard four corners to a side length of 5 cm cube, and then fold along the dotted line into a cuboid What's the volume in cubic centimeters?