![](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>)
Cut a cuboid 16 cm long, 8 cm wide and 10 cm high into two cuboids of exactly the same shape and size. What is the maximum and minimum surface area of the cuboid?
The maximum cross section is 16x10, the height is 4 and the surface area is (16x10 + 16x4 + 10x4) x2 = 528
The minimum cross section is 8x10, the height is 8, and the minimum surface area is (8x10 + 8x8 + 8x10) x2 = 448
A rectangular food box is 8 cm long, 6 cm wide and 10 cm high. If a circle of brand paper is pasted around the food box, how many square meters is the area of the brand paper at least?
(8 × 10 + 6 × 10) × 2 = (80 + 60) × 2 = 140 × 2 = 280 (square centimeter); 280 square centimeter = 0.028 square meter
The length of a cuboid is 10 cm, the width is 8 cm, and the height is 5 cm. After cutting it into two identical cuboids, the surface area will increase at least () square cm
The length of a cuboid is 10 cm, the width is 8 cm, and the height is 5 cm. After cutting it into two identical cuboids, the surface area will increase at least (80) square cm
As shown in the figure, in square ABCD, CE ⊥ Mn, if ∠ MCE = 35 °, then the degree of ∠ anm is______ ．
If NP ⊥ BC is made to P through N, then NP = DC, ∫ MCE + ∠ NMC = 90 °, MNP + ∠ NMC = 90 ° and ∪ MCE = ∠ MNP, ∪ MNP = ∠ mcenp = CB ∠ NPM = ∠ CBE, ≌ BEC ≌ PMN, ∪ MCE = ∠ PNM and ∪ anm = 90 ° - MCE = 55 ° in △ MnP and △ ECB
6 / 7: simplify ratio and calculate ratio
It seems that I have to say something theoretical first: reduction ratio, as the name suggests, is to reduce a ratio to the simplest form, that is to say, the numbers on both sides of the comparison sign (colon) cannot be reduced, and the numbers on both sides are integers. Multiply two numbers by a number or divide them by a number at the same time, and the ratio will not change
One operation of quadratic radical
Sum of radical n (n + 1) (n + 2) (n + 3) + 1
N(N+1)(N+2)(N+3)+1
=[N(N+3)][(N+1)(N+2)]+1
=(N^2+3N)[(N^2+3N)+2]+1
=(N^2+3N)^2+2(N^2+3N)+1
=(N^2+3N+1)^2
So the root n (n + 1) (n + 2) (n + 3) + 1
=N^2+3N+1
The area of the circle in the figure is exactly 12 times that of the rectangle ABCD. The length of AB is 6.28cm, and the area of the shadow is______ Square centimeter
3.14 × (6.28 △ 2) 2 × 1.5 = 3.14 × 9.8596 × 1.5 = 30.959144 × 1.5 ≈ 46.44 (square centimeter); answer: the area of shadow part is 46 square centimeter. So the answer is: 46.44
Given that M & # 178; - 2m + 1 and | n-2 | are mutually opposite numbers, it is necessary to find the value of (m-n)
That is (m-1) &# 178; + | n-2 | = 0
So M-1 = n-2 = 0
m=1,n=2
So M-N = - 1
The first volume of the third grade is 20 ways of mathematical calculation, asking for help
1) 5.7-1.8= 2) 99×84= 3) 1.02×4= 4) 7.34-4= 5) 0.45÷0.15= 6) 800×0.03= 7) 3.27-1.27+4.9= 8) 11×25= 9) 0.14×50= 10) 0.81÷0.27= 11) 0.24×0.5= 12) 18.2+1.8= 13) 1.5×3= 14) 0.16×30= 15) 5.38+0.4...
If the length and width of a rectangle are increased by 3 cm, the area will be increased by 54 square cm. The perimeter of the original rectangle is______ Decimeter
As shown in the figure, (54-3 × 3) △ 3 × 2 = (54-9) △ 3 × 2 = 45 △ 3 × 2 = 30 (CM) = 3 (decimeter)
RELATED INFORMATIONS
- 1. A rectangular food box is 8 cm long, 6 cm wide and 10 cm high. If a circle of brand paper is pasted around the food box, how many square meters is the area of the brand paper at least?
- 2. A cuboid food box is 10 cm long, 8 cm wide and 12 cm high. Stick a circle of brand paper around it. How many square centimeters should the area of brand paper be at least?
- 3. In a cylindrical bottle with a bottom radius of 10 cm, the water depth is 8 cm. To put a piece of iron in the bottle, which is 8 cm in length and 15 cm in width and 15 cm in height, how many cm does the water surface rise when the iron is placed vertically in the water?
- 4. In a cylindrical bottle with a bottom radius of 10 cm, the water depth is 8 cm. To put a piece of iron in the bottle, which is 8 cm in length and 15 cm in width and 15 cm in height, how many cm does the water surface rise when the iron is placed vertically in the water?
- 5. In a cylindrical glass tank with a bottom radius of 10 cm and a water depth of 8 cm, an iron block of 8 cm in length and width and 15 cm in height should be placed in the tank 1. How many centimeters will the water surface rise when the iron block is placed horizontally in the water? 2. Put the iron block in the water vertically, how many centimeters will the water rise?
- 6. A cube lead block with an edge length of 8 cm is installed in a cuboid glass tank of 16 cm long, 10 cm wide and 20 cm high, and then some water is put into the tank to completely submerge the cube lead block. When the lead block is taken out of the tank, how many cm will the water in the tank drop?
- 7. A cuboid is 8 cm in height, 1 / 2 in width and 5 / 4 in width. The cuboid is () cm in width, () cm in length, () cm in edge length, () m3 in volume and () cm2 in surface area
- 8. The circumference of the bottom of a cuboid is 36 cm, and the height is 8 cm. What is the total length of the edges of the cuboid?
- 9. The circumference of the bottom of the cuboid is 36 cm and the height is 8 cm. The total length of the edges of the cuboid is () cm
- 10. Use three cuboids that are 3cm long, 2cm wide and 1cm high to form a large cuboid with the smallest surface area. How many square centimeters is the surface area of this cuboid
- 11. Cut a cube with an edge length of 8 cm into two cuboids of the same shape and size. The volume () and surface area () of each cuboid
- 12. A rectangle shaped plexiglass is 10 cm long, 8 cm wide and 6 cm high. Cut the largest cube on the plexiglass and find the rest
- 13. A cuboid glass jar is 4 decimeters long, 3 decimeters wide and 5 decimeters high. After pouring water, the water depth is 3.5 decimeters, and the poured water is () liters A. 60B. 42C. 52.5
- 14. Pour 18 liters of water into a rectangular glass tank 4 decimeters long, 3 decimeters wide and 2 decimeters high. How many decimeters is the distance between the water surface and the tank mouth?
- 15. There is water in a sealed rectangular glass fiber reinforced plastic. The lengths of the three edges intersecting one vertex of the glass jar are 10 cm, 6 cm and 5 cm respectively. Put the glass jar on the water surface in three different ways. The minimum height of water is 2 cm. What is the maximum height of water? (please draw a sketch and calculate it.)
- 16. In a 6-decimeter-long, 4-decimeter-wide and 3-decimeter-high rectangular glass jar, the water depth is 2 decimeters, The water depth becomes 2. Find the volume of the iron ball
- 17. A 40 cm long, 20 cm wide and 30 cm high cuboid glass jar is 18 cm deep. Now an iron ball is completely immersed in the water, and the water surface rises to 25%
- 18. As shown in Figure 1, the water depth in a closed rectangular glass tank is 3 cm. If the glass tank is placed as shown in Figure 2, how many cm is the water depth inside?
- 19. When a rectangular iron block with a bottom area of 4 square centimeter is put into a glass container with a bottom area of 20 square centimeter, the water in the container rises by 1 centimeter Ask for the height of the iron
- 20. A cuboid shaped glass container, 40 cm long, 30 cm wide and 50 cm high, is waterproof and 3 decimeters high. Now there is a piece of iron in it, which is completely immersed in water, and the water level is 35 cm high. How many kg of iron is put in it (7.8 kg of iron per cubic decimeter)