I can t learn the knowledge of cylinders and cones, I think it s so difficult. What to do?

There doesn't seem to be a question in this question, what does it require? I understand that according to the context, it should be to find how much coal there is. According to the sentence "weight tons per cubic meter of coal" and then backwards, is to find how many cubic meters (volume), the volume formula of the cone is the bottom area height one-third, known height, that is to find the bottom area, the bottom area is the square of the radius, and then know the diameter of the bottom surface, so what is so rare?

If you can't figure out the unit conversion, then mark the numbers of the equation with units when you draft them, and then eliminate them according to multiplication and division, and the rest is... If you don't understand cylindrical cones and don't have abstract thinking, then make a model by yourself and deepen your understanding in the process.

This is actually you first calculate the volume of the cone, and then calculate how many tons, you can (this time you don't do well in the exam, in fact, I'm the same, I always feel that the cylindrical cone calculation is a lot, and the wrong step, the whole question will be wrong, since you don't do well in the exam, then the teacher has to listen to how to make the correct answer when talking about the exam paper, if you haven't understood, you can ask your classmates, if you really don't understand, then you have to ask the teacher, although the teacher will also say a few words when asking the teacher, But the teacher will still tell you how to do it)

Memorize more formulas, practice more, math is like that, and proficiency in formulas is the premise!

Actually, this one is very simple, as long as you understand the meaning of the question.

As long as you listen carefully to the lecture and memorize the formulas.

Learning is hard work, and sometimes it's like throwing it into a pan of oil and frying.

1. Characteristics of the cylinder:

1) Characteristics of the bottom surface: The bottom surface of the cylinder is two circles that are completely phased.

2) Characteristics of the side: The side of the cylinder is a curved surface.

3) Characteristics of height: Cylinders have an infinite number of strips high.

2. The height of the cylinder:

The distance between the two bottom surfaces is called the height.

3. Side view of the cylinder:

When along the height, the diagram is rectangular; When the bottom circumference and height are equal, the map is square along the elevation; When not along height, the diagram is a parallelogram.

4. The side area of the cylinder:

The side area of the cylinder = the perimeter height of the bottom surface, which is represented by letters as: S side = CH.

5. The surface area of the circle:

The surface area of the cylinder = side area + 2 base area. That is, S table = S side + 2S bottom.

6. The volume of the cylinder:

The size of the space occupied by the cylinder is called the volume of the cylinder. v=sh

7. Cone: The rotating body surrounded by the surface formed by the rotation of one right-angled side of a right-angled triangle is the axis of rotation, and the surface formed by the rotation of the other two sides is called a cone. The right-angled side is called the axis of the cone.

8. The height of the cone:

The distance from the vertex of the cone to the center of the base is the height of the cone.

9. Characteristics of the cone:

1) The characteristics of the bottom surface: the bottom surface of the cone is a circle.

2) Characteristics of the side: The side of the cone is a curved surface.

3) High characteristics: The cone has a high strip.

10. The bus bar of the cone:

The radius of the fan formed by the sides of the cone, the distance from the point on the circumference of the base surface to the vertex. The cone has an infinite number of busbars.

11. The side of the cone:

The side of the cone is along the busbar, is a fan, the arc length of this fan is equal to the circumference of the bottom surface of the cone, and the radius of the fan is equal to the length of the bus bar of the cone.

12. The side area of the cone = the circumference of the bottom surface (the length of the arc of the figure) busbar.

13. The volume of the cone:

The size of the space occupied by a cone is called the volume of the cone. The volume of a cone is equal to the volume of a cylinder of equal height to its base 1 3.

According to the cylindrical volume formula v=sh (v=rrh), the conic volume formula is obtained: v=1 3sh

14. The relationship between the cylinder and the cone:

1) The volume of a cone, which is equal to the bottom of the cylinder, is one-third of the volume of the cylinder.

2) Between a cone of equal volume and height and a cylinder (equal bottom and equal height), the base area of the cone is three times that of the cylinder.

3) Between a cone with equal volume and base area and a cylinder (contour and contour), the height of the cone is three times that of the cylinder.

On the basis of understanding the formula, you must memorize it, and do more questions to practice well, in fact, the main thing is the surface area and volume of the cone and cylinder, and it is also easy to understand that the surface area is the addition of the area of the rectangle and the circle, so it is very important to learn the area of the circle and the rectangle.

It's the same with the cone, and the fan area is also based on the area of the circle, and it's a matter of multiplying by a fraction of a percent, and the volume problem is that the base area is multiplied by the height of the base area of the cone, and the base area of the cone is 1 3 multiplied by the height.

It is necessary to establish a perceptual understanding of the three-dimensional space.

Play with blocks and three-dimensional painting.

First of all, let's look at what is a cylinder and what is a cone. (It is very clear in this book, I will not repeat it here) remember their relevant calculation formula: side area of the cylinder = surface area of the ch cylinder = 2 * base area + side area (note that some questions are for the surface area without the base area, or the surface area with only one bottom surface.

It is important to analyze specific problems and see the meaning of the topic).

The volume of the cylinder = r 2*h

Volume of the cone = (1 3) * r 2 * h

Note that the ratio of the volume of a cylinder to a cone of equal height is 3:1, then the related problems include a cylinder and a cone of equal volume, a ratio of 1:3 for the same base area, and so on.

This is only the content of the primary school part, and if you have any questions, you can **.

Do more questions, summarize more methods, there are no shortcuts.

Memorize the formula... These are not difficult to learn...

Use your brain more, calculate more, and don't know how to ask more. In short, be diligent.

Cylinder: Surface area: square of radius * 2 + diameter * height = base area * 2 + side area.

Volume: Base area * high.

Cone: Volume: Square of radius * 3 high

The knowledge of cylinders and cones is nothing more than to know the calculation of their volume and surface area, as long as you remember the formulas of their volume and surface area, and also be good at analyzing the problem, according to the information provided by the problem, compare the formula, and find the unknown quantity required.

, the name of each part of the cylinder.

The cylinder is composed of three parts: two undersides and one side.

1) Bottom surface: The two circular faces of the cylinder are called the bottom surface.

2) Side: The surface around the cylinder is called the side.

3) Height: The distance between the two bottom surfaces of the cylinder is called height.

s=chs=ch+2s

v=sh2, the name of the part of the cone.

1) Bottom surface: The round surface of the cone is its bottom surface.

2) Side: The surface around the cone is called the side.

3) Height: The distance from the vertex of the cone to the center of the bottom is the height of the cone.

v=1/3sh

After 4 minutes, the volume of water in A is 2L+, the volume of water in B is 10cm in the bottom diameter, then the radius is 5cm, the bottom area is square centimeters, then the height of water in B is cubic centimeters The height of ab is equal to the height of square centimeters, then the bottom area of A is divided by the height, about 1000000 is , then the square of the radius of A is open, and the diameter is equal to 15cm.

The side area of the cylinder = the circumference of the bottom surface x the height The surface area of the cylinder = the sides of the cylinder + the area of the two bottom surfaces.

The volume of the cylinder = base area x height = v = sh

Conical: 1 3v = 1 3sh

First of all, keep in mind the formula, multiply the base area by the height, which is the cylinder; The third of the cylinder, is the cone, which is the volume.

In terms of surface area, the cylinder is the area of two circles plus the rectangle in the middle, imagine a cylindrical cup, so the height of the rectangle is the height of the cylinder, and the width is the circumference of the cylinder.

Cylinders and cones, if there is an application problem, there will be such an application problem, such as finding the volume of the round table. The round table has not been learned, but it can be seen as a large cone being cut off a small cone, and the volume of the two can be subtracted.

That's right, first memorize the formula, then remember the concept, then remember the main point of the teacher's lecture, don't be lazy, it's better to take notes.

The application questions are generally more flexible, more in the granary, direct calculation, roller (must not count two bottoms), as well as swimming pool plastering cement and so on.

V-column: V-cone = R-column H-column: R-cone H-cone 3=3 (R-column: R-cone ) H-column: H-cone) The score obtained is the volume ratio of the two.

R-pillar: R-cone = (V-pillar H-column): 3V-cone H-cone) = (V-column: 3V-cone) H-cone: H-column) The score obtained is the ratio of the radius of the two.

H-pillar: H-cone = V-pillar R-column: 3V cone R-cone = (V-column: 3V cone) (R-cone: R-pillar) The score obtained is the height ratio of the two.

It's a box, if they have the same base area and volume, then the height of the cylinder and the height of the box are equal, because the volume of both of them = base area x height.

The volume ratio of a cylinder to a cone is: 4 : 9 3