Help solve math problems!! One more math problem!!

A cylinder consists of two bases, one side.

So a piece of paper can do 3 sides, which is the side of 3 cylinders.

You can make 4 of the bottom surface alone, and you can make 2 sides of the cylinder with one sheet.

Therefore, at least 2 sheets of paper are needed for the side (2*3=6 cylinders), and 3 sheets of paper are used for the bottom surface of 2*3=6 cylinders.

That is, at least 5 of these pieces of paper are needed to make 6 cylinders so that the pieces of paper are not wasted.

If you don't understand, please ask!

Have fun!

How can you not waste it if you do the bottom? The bottom is round, unless you only think about the area.

5 sheets of paper, make 6 cylinders, (two of them for the sides, three for the bottom.) (Keep in mind that a cylinder has two bases.) ））

Each cylinder needs 1 side, 2 bottom surfaces, each side needs 1 3 paper, and the bottom surface of each cylinder is the two bottom surfaces need 1 2 papers, that is, you can find the least common multiple of 2 and 3. That is, 6 cylinders, you need to make 2 sheets of paper on the side and 3 sheets of paper on the bottom surface, a total of 5 pieces of paper.

Another way: one side of each cylinder needs 1 3 sheets of paper, and the two bottom surfaces need 1 2 sheets of paper, that is, each cylinder needs paper 1 3 + 1 2 (one-third plus one-half) = 5 6 sheets of paper. So at least an integer is 5 sheets of paper and 6 cylinders.

Equation solution: Let x pieces of paper be used as the side and y sheets of paper should be used as the bottom surface. A total of (x+y) pieces of paper are required.

2*3x=4y (one side with two bottom surfaces, so the number of bottom surfaces is twice that of the side) 6x=4y to find the minimum value is x=2, y=3

So a total of 2+3=5 pieces of paper are needed.

A: A minimum of 5 pieces of paper is required.

3 for the bottom and 2 for the sides.

This makes 6 cylinders.

A piece of paper can do 3 on the side, 4 on the bottom surface of the single (one on the top and bottom, that is, two cylinders), the least common multiple of 3 and 2 is 6, that is, 6 cylinders, 5 sheets of paper, 2 sides, 3 bottoms.

Categories: Education, Science, >> Learning Aid.

Problem description: The inner angle of a polygon increases by the same number of degrees from small to large, where the smallest angle is 100 degrees, and the largest angle is 140 degrees, find the number of sides of this polygon.

Analysis: Sum of the outer angles of the polygon = 360 degrees.

Maximum outer angle = 80 degrees.

Minimum outer angle = 40 degrees.

80+40）*x/2=360

x=6, so the polygon is a 6-sided polygon.

I have two solutions, I don't know if you can understand it.

Solution 1: From the boat down the water, against the current, a total of 8 hours, can be obtained with less than 4 hours of the water, more than 4 hours against the water.

According to "20 kilometers more than the reverse water per hour" and "60 kilometers more in the first 4 hours than in the last 4 hours", it can be seen that 60 kilometers is the distance in the first 4 hours of the boat with the same time with the water than in the same time in the last 4 hours.

Find the boat 60 20 = 3 hours; 8-3 = 5 hours against the current.

The distance traveled in 5 hours against the water is less than that in 5 hours along the water: 20 5 = 100 (kilometers) The distance traveled by 3 hours in the river is the same as the distance traveled in 5 hours against the water, then the distance traveled in 2 hours along the water is 100 kilometers, that is, the number of kilometers traveled per hour along the water: 100 (5-3) = 50 (kilometers) The distance between the two ports of A and B: 50 3 = 150 (kilometers).

Solution 2: The next 4 hours will definitely be driving against the water.

4 hours against the water is 20 4 = 80 kilometers less than 4 hours along the water, and it is known that the first 4 hours are 60 kilometers more than the next 4 hours.

So in the first 4 hours, (80-60) 20=1 hour is driving against the water, so driving with the water for 4-1=3 hours, driving against the water for 8-3 = 5 hours, driving against the water speed: speed against the water = 5:3

Therefore, the speed of the river is 20 (5-3) 5 = 50 km per hour, and the distance between the two ports is 50 3 = 150 km.

The title says "It is known that the first 4 hours are 60 kilometers longer than the next 4 hours" - indicating that the next 4 hours were all against the current.

If the distance traveled 4 hours after the ship is (full -x) km, then the distance traveled 4 hours before the ship is (full distance + x) km

The first 4 hours are 60 kilometers more than the next 4 hours", 2 x km more, so x = 30 ships sail 20 km per hour more than the counter current, if the first 4 hours are all sailing downstream, it should be more than the last 4 hours: 20 4 = 80 km and the actual first 4 hours are only 60 km more than the last 4 hours - 30 km downstream + 30 km against the current - 80-30 = 50km

Explain that the time to sail 30 km against the current is the same as the time to sail 50 km downstream.

Then the ratio of the speed of the ship sailing downstream to the speed of sailing against the current is 50:30=5:3, so the speed of the ship sailing against the current is: 20 (5-3) 3=30 (km h), and the distance between the two ports of A and B is: 30 4+30=150 (km).

Set: The speed of the ship is x, and the two ports of A and B are y kilometers apart.

Because the downstream traveled 20 kilometers per hour more than the reverse current, the downstream speed was (x+10) and the reverse water velocity was (x-10), and it took 8 hours to share.

So there is y (x+10) + y (x-10) = 8....1)

And because the first 4 hours are 60 kilometers longer than the next 4 hours, it is easy to know that the last four hours are all against the current, and the distance against the water is Y-60.

So there is (y-30) (x-10)=4 ...2) y=4x-10....3)

Bringing Eq. (3) into Eq. (1) gives us x=40 km, hour y=150km.

Let me help you list the equations, and you can understand what they are: (x+30) v A+(x+3o) (v+2o)=8 (x+30) v+60-a v+20=60

The volume of each small cube is cubic meter = cubic power of l.

l is the side length of the small cube.

l = and the cube has 6 faces.

and the area is equal.

So the area of each small cube is 6*