A square with a side length of 6.28 cm has a circumference equal to that of a circle. The diameter of the circle is () cm and the area is () square centimeter

A square with a side length of 6.28 cm has a circumference equal to that of a circle. The diameter of the circle is () cm and the area is () square centimeter

A square with a side length of 6.28 cm has a circumference equal to that of a circle. The diameter of the circle is (8) cm, and the area is (50.24) cm2
The formula is as follows:
6.28x4 = circumference = 3.14x diameter, diameter = 25.12 △ 3.14 = 8
Radius = 8 △ 2 = 4
Area = 3.14x4 ^ 2 = 50.24cm2

The area ratio of square and circle with equal circumference is () if the side length of square is equal to the diameter of circle, then the circumference of square () the circumference of circle

Let the circumference be 2R π
The area of the square is (2R π / 4) 2 = π 2 / 4
Circular area = π R 2
The area ratio is square: circle = π: 4
Let the diameter be 2R
Square perimeter = 8R
Circumference = 2R π
8R>2Rπ
So the circumference of a square is greater than that of a circle

If the side length of a square is equal to the diameter of a circle, then the circumference of a square must be greater than that of a circle

Yes
For example, the side of a square is a and its circumference is 4a
The circumference of a circle with diameter a is a * π = 3.14a
Because 3.14 < 4,
So 3.14a < 4a
Therefore, if the side length of a square is equal to the diameter of a circle, then the circumference of a square must be greater than that of a circle

0

Let the diameter of the circle be D, then the side length of the square is also d,
The circumference of the circle: 3.14 × d = 3.14 D,
Circumference of square: 4D,
Because 3.14 d < 4 d,
So it is correct that the circumference of the circle must be less than that of the square
So the answer is: √

The unit price of rice is fixed. How much rice to buy and how much money to spend? The circumference of a circle and its diameter? The circumference and side length of a square? The area of the square and it Perimeter? The bottom of the triangle is fixed, its area and height? Judge whether the two quantities in each question are in positive proportion, and explain with the formula reason,

The following format is taught by our teacher. I don 't know if it is suitable for you
Rice unit price is fixed, how much rice to buy and how much money to spend?
Because the amount of money used: quantity = unit price (certain)
Business certainty
Therefore, the amount of rice and the amount of money used in a positive proportion
The circumference of a circle and its diameter?
Because the circumference of a circle: its diameter = π (certain)
Business certainty
So the circumference of a circle is proportional to its diameter
The circumference of a square and its side length?
Because the circumference of a square: its side length = fixed value (certain)
Business certainty
So the circumference of a square is proportional to its side length
The area of a square and its circumference?
There is no correlation between the two quantities, so they are out of proportion
The base of a triangle is fixed, its area and height?
There is no correlation between the two quantities, so they are out of proportion

The circumference of an equilateral triangle is equal to that of a circle. One side of an equilateral triangle is 6.28. What is the radius and area of the circle?

C△=3×6.28=18.84
C circle = 18.84 = 2 π R, r = 3
S circle = π r? = 3? × 3.14 = 28.26

The circumference of an equilateral triangle is equal to that of a circle. One side of an equilateral triangle is 6.28. What is the radius and area of the circle?

Circumference of circle = circumference of equilateral triangle = 6.28 × 3 = 18.84
So radius = 18.84 △ 3.14 △ 2 = 3
So the area = 3.14 × 3? 2 = 28.26

The circumference and area of a semicircle are equal to half of the circumference and area of the circle ()

X
Half the area
Perimeter is not

The sizes of 218 × 310 and 210 × 315 were compared

∵218×310=28×210×310=28×610，210×315=210×310×35=610×35，28＞35，
∴218×310＞210×315．

(3 times 10 to the - 15th power) times (5 times 10 to the - 5th power)

=3 × 5 × 10 - 15th power × 10 - 5th power
=15 × 10 (- 15-5) power
=The - 20th power of 1.5 × 10 × 10
=1.5 × 10 to the power of 1-20
=1.5 × 10 - 19th power