Mathematics is a controversy over the problem of calculating the circumference of a circle!

Is this a strict requirement for elementary school students? Do you have to write formulas?? Isn't it good that this answer is correct? Now this school really can't help it.

In general, elementary school math answers are not required to write formulas.

But after junior high school and high school, you have to be formal, and you have to write the formula @@ when you have a certain framework for answering questions

Your dad is right, this is a matter of habit, don't write the formula when the teacher first has to analyze what your formula means, after writing the formula, it is clear at a glance, although this question is very simple, the impact is not great, but what if it is a complex physics formula in high school? If you don't write formulas, no one will understand them (which is not good for checking for mistakes), so it's best to get into good habits now.

Is the first question a semicircle? That should be: 2 * the arc length of the semicircle), plus 2 = plus that straight line) Question 2: Because the remaining length is 5, the width is still 2, so the radius is still 2, and this is the result by using the formula.

That's great, you can try it. uヲd

1 2 * the arc length of the semicircle), plus 2 = plus that straight line)2 because the remaining length is 5, width 2, radius 2

lz,, I suggest you still listen to your dad! I don't know what grade you are in, anyway, the teacher marks the paper based on your steps to give points, if you don't write the formula and the result is calculated wrong (for example, I believe you won't be wrong) then the teacher will not give a point, if you write the formula, but the result is wrong, then the teacher will know that you will do this question, but carelessly miscalculated. Then out of 10 points, you can get at least 8 points.

Moreover, in high school or even college, there is no formula, only the result, and the teacher will definitely deduct your points (generally half of 10 points) Or write formulas and develop good habits. When you were in high school, you could just write formulas and bring in the data, and it didn't count as 12 to get 10 points.

As for what the upstairs said about using the formula to convert the diameter into a radius, don't listen to it, there is a formula that is directly multiplied by the diameter of pi.

Are you in elementary school or junior high school?

In elementary school, it's just your answer.

Junior high school is your dad's.

I'm serious, and the best answer is to write the formula.

The problem is to find the circumference of a circle: meters.

1100 minutes.

Every Wang Yuqing minutes line.

71 cm drowsy grip (m).

Need. 1100 minutes.

The minute hand of a wall clock is 15 centimeters long, and after 15 minutes, how many centimeters does the tip of the minute hand travel? What about 60 minutes?

Distance = 2 15 15 60 =, 60 minutes distance = 2 15 = 2After three-quarters of an hour of a wall clock, the tip of the minute hand has traveled exactly centimeters, how many centimeters is the length of the minute hand?

Three-quarters of an hour is three-quarters of a circumference.

So there is the length of the minute hand =

3.The length of a wall clock minute hand is twice the length of the hour hand, and the tip of the hour and minute hand has traveled exactly a centimeter, so how many centimeters has the hour hand traveled?

Length of the minute hand =

Length of the hour hand = 6

So the hour hand has gone approximately = 4 2 1 12=

(1) The length of the minute hand is the radius of the circle.

Perimeter = 2* *r = 2 * * * 15 = 30

The minute hand is 60 minutes in a week. Then 15 minutes walked a quarter of the week. So the distance s=30 4=

2) Set the length of the minute hand to r

Perimeter = 2 * * r Distance s = (3 4) * Perimeter = (3 2) * r = Solve the equation to get r = 20

3) Set the length of the hour hand to x, then the length of the minute hand is.

If the tip of the minute hand of one hour is exactly one centimeter, then the circumference of the minute hand is centimeter 2**

The solution is x=4 so the length of the hour hand is 4

Circumference of the hour hand = 2 * * x =

If the hour hand goes around for 12 hours and the minute hand travels for one hour, then the length of the hour hand is one-twelfth of a revolution s = the circumference of the hour hand 12

The tip of the minute hand has passed: 1 4 2 15 The tip of the minute hand has been passed by the tip of the 60 minute hand: 2 15

2. The length of the minute hand =

3. The length of the minute hand =

Length of the hour hand = 6

The length of the 1-hour hour hand = 1 12 4 2

1. After 15 minutes, the distance traveled by the tip of the minute hand is 15 cm, and after 60 minutes, the distance traveled by the tip of the minute hand is 15 cm2, and the length of the minute hand is centimeter.

3. The hour hand has gone by centimeters.

1.Distance = 2 15 15 60 =, 60 minutes distance = 2 15 = 2Three-quarters of an hour is three-quarters of a circumference, so there is the length of the minute hand =

3.Length of the minute hand =

Length of the hour hand = 6

So the hour hand has gone approximately = 4 2 1 12=

It's that simple.

The area of the circle is equal to the radius multiplied by 2*pi, and the length of the minute hand is the radius, so calculate it yourself.

m)25 2=m)

cm) m = 4710 cm 4710 laps).

centimeter) centimeter) centimeter) centimeter).

Circumference = 4 r = 20

Rope length = circumference + 2 diameter = 20 + 20

The circumference of the circle is 2, and this figure can be just enough to form a circle. 2πr=8π

Answer: The circumference of the Peihe part of this shade is the circumference of a circle with a radius of 8 2 centimeters, so it is: centimeters.