The formula for calculating the circumference of a circle is C2r, where C and r are inversely propor

The formula for calculating the circumference of a circle is c=2 r, where c and r are inversely proportional. Wrong.

Because: c=2 r, c:r=2 (definitely), c and r are two related quantities, c changes with the change of r, 2 is certain, that is, the ratio of the corresponding number of c and r is certain.

So c and r are in direct proportional relationship.

quotient is certain, and the two quantities are proportional; The product is certain, and the two quantities are inversely proportional.

Proportionality: two related quantities, one quantity changes, the other quantity also changes, if the ratio (quotient) of the two corresponding numbers in the two quantities is constant, these two quantities are called proportional quantities, and their relationship is called proportional relationship. If the letters x and y are used to denote the two related quantities, and k is used to denote their ratios, the proportional relationship can be expressed by the following formula:

y x=k (definitely).

Inverse proportionality: two related quantities, one quantity changes, the other quantity also changes, if the product of the two corresponding numbers in the two quantities is constant, these two quantities are called inversely proportional quantities, and their relationship is called inverse proportional relationship. If the letters x and y are used to represent the two related quantities, and k is used to represent their products, the inverse proportional relationship can be expressed by the following equation:

xy=k (definitely).

Because: c=2 r, so: c:r=2 (certainly), it can be seen that c and r are two related quantities, c changes with the change of r, 2 is certain, that is, the ratio of the corresponding number of c and r is certain, so c and r are proportional

So the answer is: false

Because :c=2 r, :c:

r=2 (certainly), it can be seen that c and nucleated r are two related quantities, c changes with the change of the preparation of the digging r, 2 is certain, that is, the ratio of the corresponding number of c and r is certain, so c is proportional to the wild r

So the answer is: false

Summary. Hello, in the circumference formula of a circle c=d, c is directly proportional to d. Because, c d is a constant. By definition: when the quotient of two numbers is fixed, the two quantities are proportional.

In the circumference formula of a circle c= d, is c proportional to d and why?

Hello, Jiankai in the circumference formula of a circle c= d, c is directly proportional to d. Because, c d is called by Chang Min with several manuscripts. By definition: when the quotient of two numbers is fixed, the two quantities are proportional.

I'm not asking the question above.

You can take a picture of the question and show it to me.

Because c = d, so c d = (definitely), is the corresponding ratio is certain, so c and d are proportional to the slippery note that although d is a related rock or two quantities, it is a fixed quantity and cannot change with the change of the variable d, so it is disproportionate to d rough and compatible.

The formula for the circumference of a circle c = vultures is not true, if it is written as c two d vultures are not correct.

Please reply. The formula for the circumference of a circle c = d is correct, and the multiplication of pi by the diameter, if it is written as c two d vultures, is not standard and incorrect.

In this fifth grade, you will learn to use letters to represent numbers, the product of letters and numbers, and the numbers should be written first.

Is it wrong for the student to write like this?

I haven't learned how to use letters to represent numbers, and I can calculate it correctly.

Just write the formula for the circumference of the circle.

It is the knowledge of the sixth grade.

Well, it depends on whether the teacher changes it strictly, because the mathematical writing method should be standardized.

That's wrong, I've learned the rules of writing letters to represent numbers: when a letter is multiplied by a number, the number is usually written in front of the letter.

For example, if the formula for the area of a circle is r, if it is written as r, it is not a standard way to write.

When using letters to represent numbers, the number can usually be omitted and not written, or the multiplication sign between the letter and the letter can be omitted, or the number should be written in front of the letter when the multiplication sign is omitted.

The circumference of a circle is: 2 r 2= r or d 2, and the circumference of a semicircle is: 2 r 2+2r or d 2+d;

So the answer is: true

When deriving the formula for calculating the area of a circle, we divide the circle with radius r into several parts, and then put the circle into a ridge to prepare an approximate rectangle, then the width of the rectangle is r, and the length is 2 r 2= r, so the area of the rectangle r r= r2

That is, the formula for the area of the circle is r2

This method is called "turning the liquid field into a circle".

So the answer is: turn a circle into a square

In the formula for calculating the circumference of a circle c=2 r, 2 is certain, and when c is certain, then r is also certain, so in this relation, all quantities are certain, so when c is certain, and r are not in any proportion, so "when c is certain, and r is inversely proportional" is wrong So the answer is: false