A wire is surrounded by a circle with a diameter of 4cm. If it is surrounded by a rectangle, the length of the rectangle is 6cm, then the width of the rectangle is () cm Urgent! According to the sentence "the width of a rectangle is the radius of a circle" in the book, I am right! Asked the teacher only said that this circle has two diameters! What's the matter There are three options A2CM　B0．56CM　C0．28CM I choose a, but the teacher said to choose C, what's the matter?

A wire is surrounded by a circle with a diameter of 4cm. If it is surrounded by a rectangle, the length of the rectangle is 6cm, then the width of the rectangle is () cm Urgent! According to the sentence "the width of a rectangle is the radius of a circle" in the book, I am right! Asked the teacher only said that this circle has two diameters! What's the matter There are three options A2CM　B0．56CM　C0．28CM I choose a, but the teacher said to choose C, what's the matter?

3.14 × 4 = 12.56 cm
12.56÷2-6
=6.28-6
=0.28 cm

Mr. Wang now has a 50cm long wire. Due to the need of class, Mr. Wang wants to make the wire into a ring with an area of 300cm. Do you think Mr. Wang can make it? And explain the reason

A: Mr. Wang can't make the circle with an area of 300 square centimeters. Because: when making it, the wire with a length of 50 cm becomes the circumference of the circle. If the circumference of the circle is 50 cm, its radius is 50 △ 3.14 △ 2 ≈ 8 cm, and the maximum area of the circle can only be 3.14 × 8 × 8 = 200

Use a piece of iron wire to encircle a rectangle which is 4 / 9 of its width and length. If it is encircled into a square, the long side must be shortened by 5cm and added to the short side
How long is this wire?

The difference between length and width is 2 * 5 = 10
10/（1-4/9）=18
18-10=8
Total length = 2 * (18 + 8) = 52

With a piece of iron wire, it just forms a rectangle 4 / 9 in width and length. If it is changed into a square, the length must be shortened by 3.5cm. How big is the iron wire
Long?

20 + 20 + 8 + 8 = 56 (CM)
56 / 2 / 4 = 7 (CM)
A: the side length of the two squares is 7 cm

The area of a rectangle, a square and a circle enclosed by three wires of the same length is a B C, and their size relationship is ()

Suppose the length of the wire is 36, the area of the rectangle is the largest, close to 81, but less than 81, and the area of the square is 81,
The circle area is 108, so c > b > a,
Give it to me,

A piece of iron wire is 6.28dm long, which can be divided into a square and a circle. How many square decimeters is the area of the circle larger than that of the square?

Side length = 6.28 △ 4 = 1.57 decimeters
Radius = 6.28 △ 3.14 △ 2 = 1 decimeter
Large = 1 × 1 × 3.14-1.57 × 1.57 = 0.6751 square decimeter

A square frame with side length of 6.28 cm is straightened to form a circle. What is the area of the circle?

2 = 4 (CM), 3.14 × 42, = 3.14 × 16, = 50.24 (square cm). A: the area of a circle is 50.24 square cm

Two 6.28dm long iron wires, one is surrounded by a square, the other is surrounded by a circle. What percentage of the area of a square is that of a circle?

(6.28 ﹣ 4) 2 ﹣ 3.14 × (6.28 ﹣ 3.14 ﹣ 2) 2, = 1.572 ﹣ 3.14 × 12, = 2.4649 ﹣ 3.14, = 0.785, = 78.5%; a: the area of a square is 78.5% of that of a circle

Two 6.28dm long iron wires, one is surrounded by a square, the other is surrounded by a circle. What percentage of the area of a square is that of a circle?

(6.28 ﹣ 4) 2 ﹣ 3.14 × (6.28 ﹣ 3.14 ﹣ 2) 2, = 1.572 ﹣ 3.14 × 12, = 2.4649 ﹣ 3.14, = 0.785, = 78.5%; a: the area of a square is 78.5% of that of a circle

Cut a 10 cm circle into the largest square whose area is ()
You can fill in percentages, fractions or decimals in brackets

Square area: 10 × 10 = 100 (CM & # 178;)
Circle area: because it is the largest circle, it should take the side length of the square as the diameter, so the radius is 5
25×3.14= 78.5﹙cm²﹚
Percentage: 78.5 △ 100 = 0.785 = 78.5%
Brother, give me an adoption, and I will graduate from Baidu primary school as the last one