Mathematics for life Essay on cylinders and cones how to write

One day, everyone went for a walk in the park as usual, and suddenly they heard the sound of a quarrel, and when they looked closer, it turned out that it was the cylinders and cones arguing, and it was quite noisy. They're good friends, why are they arguing like this? So here's what happened:

One day, cylinders, cones, and cuboids were playing in the grass, and the cuboid casually said, "What do you think is the largest figure in the kingdom of mathematics?" The cylinder said at once

Well, no comparison, of course it's me! The cone was not happy to hear this, and hurriedly said, "Why, you are larger than me?"

The cylinder said, "Look at yourself, so thin, and you still want to fight with me." ”…The cylinder and the cone are like this, you say a word, I say a word, and the quarrel is inseparable.

There is no way to continue arguing like this, and the cylinder is clamoring to go to the "Nine Chapters of Arithmetic" to comment. "Go and go, whoever is afraid of whom", said the cone puffingly.

When he arrived at the house of Jiuzhang Arithmetic, the column said straight to the point: "Grandpa Arithmetic, you say, which of the two of us is bigger?" "Nine chapters of arithmetic said:

I don't know about this question. "How is that possible? Even Grandpa Arithmetic doesn't know."

Chapter 9 arithmetic says: "In the case of equal base and equal height, the volume of the cylinder is larger than that of the cone, but it is difficult to judge if it is not in the case of equal base and equal height". Saying that, Grandpa Arithmetic took out a large cone and a very small cylinder for them to observe, and it was obvious that the volume of this cone was much larger than that of the cylinder.

Grandpa arithmetic said angrily: "How can you quarrel like this little thing, you know, you are a family, look at your bottom is round, the sides are curved, a family, you should be united and friendly." When the cylinder and the cone heard this, they both bowed their heads in shame and said nothing more.

Since then, the kingdom of mathematics has returned to its former peace, and people often hear cheerful laughter coming from ...... distance

Teacher's comment: The volume of the cone, which is equal to the bottom and the same height, is one-third of the volume of the cylinder, based on this understanding, some students mistakenly think that the volume of the cone is smaller than the volume of the cylinder, how to solve this problem, the author uses the form of the story, vividly illustrates the relationship between the volume of the cylinder and the cone, and solves the problem that it is not easy for students to solve.

For example, when we go to the supermarket to shop, we can see a wide variety of goods, the lower end of the wine bottle is cylindrical, the box of potato chips is cylindrical, the jelly box, the small hat made of cylindrical, and so on.

Cylinders and cones.

Today, in order to have a more in-depth understanding of the content of cylinders and cones, I have collected some formulas and names for the surface area and volume of cylinders and cones on the Internet. I read about the cone:

The side area of the cone is not curved, and it is a fan.

The cone has a base, a vertex, and only one strip high.

Surface area of the cone = 1 2 Busbar Bottom surface circumference Base area Cone volume formula: v 1 3sh

I also saw that the volume of the cylinder was 3 times the volume of the cone. I thought, is that so? It just so happens that there is a pair of teaching aids of equal height cylindrical and conical at home, and both teaching aids are hollow with openings, so why don't I try it?

I first filled the cone's teaching aids with water and poured them into the cylinder, but they were not filled; I poured another "cup", but it was still not filled; poured it again, and finally filled the columns with teaching aids. It seems to be true! I filled the cylindrical teaching aids with water and poured them into the cone one by one, and sure enough, I poured three cups.

Math is amazing! I sighed from the bottom of my heart.

Hehe, I wrote it myself, please advise me)

The surface area of the cylinder = 2 base areas + 1 side area.

The volume of the cylinder = the base area multiplied by the height.

The volume of the cone = sh1|3

We have learned the calculation of the surface area and volume of cuboids and cubes, and we have a clear grasp of them. Today, I learned how to calculate the surface area of two three-dimensional figures, a cylinder and a cone. We have mastered how the volume and surface area of these two stereo figures are solved.

Now, let's analyze their volume and area.

The calculation of the volume of a cylinder is simple, and the formula is: base area x height. Using this formula, the volume of the cylinder can be calculated. If you start by only knowing the radius or diameter of the bottom surface, then you need to calculate the area of the part first, and then calculate the volume of the cylinder.

Next, let's look at the surface area of the cylinder. Finding the surface area of a cylinder is more complicated than volume. Because, first ask for the side area of the cylinder, then find the area of the upper bottom and the bottom of the cylinder, and then add the three to find the surface area of the cylinder.

Although the surface area calculation method is a bit more complicated, as long as you master the methods and formulas, practice makes perfect in the future, and you will definitely do it quickly.

Next, let's learn about the cone. A cone is a circle at the bottom that stretches upwards until the top is in the shape of a point. In fact, the volume of the cone is also easy to find, only one third more than the volume of the cylinder, that is:

Base area x height? 3。For, all cones, are 1 3 of the volume of a cylinder of the same height as the bottom.

So first calculate the volume of the cylinder and divide it by 3, which is the volume of the cone.

The surface area of the cone is not mentioned in the book, but I know it.