If a piece of square paper with a circumference of 12 decimeters is used to cut into the largest circle, then the circumference of the circle is 12 decimeters______ Decimeter

14 × (12 △ 4) = 3.14 × 3, = 9.42 (decimeter), answer: the circumference of the largest circle is 9.42 decimeter

As shown in the figure: the perimeter difference of two concentric circles is 18.84 cm, and the perimeter difference of two squares is 18.84 cm______ Cm

Let the diameter of the big circle (the side length of the big square) be D, and the diameter of the small circle (the side length of the small square) be d. & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp;, the diameter of the big circle (the side length of the big square) be d

1. Cut the rectangular paper 4 decimeters long and 3 decimeters wide into the largest semicircle. What are the perimeter and area of the semicircle?
2. The front wheel of a roller is 1.6 meters wide and 0.8 meters in diameter. It turns 15 cycles per minute. How many meters does the roller advance per minute? How big is the road it passes per minute?
3. The side length of the small square table is 1 meter. Stretch its four sides to form a round table (as shown in the figure below). Find the area of the round table
4. Make a rectangular wooden box with five boards of the same size (5 decimeters in length and 3 decimeters in width). Only one board is allowed on each side (splicing is not allowed). What is the maximum volume of the wooden box? How many square decimeters of sawn waste?
5. Measure the volume of a spherical iron block in a rectangular container with a side length of 8 cm and a height of 17 cm. The water in the container is 2 cm away from the mouth of the cup. When the iron block is put into the container, some water overflows. When the iron block is taken out, the water surface drops by 5 cm to calculate the volume of the iron ball

1. Perimeter: 3 * 3.14 = 9.42 (decimeter) area: 3 / 2 = 1.515. * 1.5 * 3.14 = 7.065 (square decimeter) 2. Advance per minute: 0.8 * 3.14 * 15 = 37.68 (meter) passing the road per minute: 1.6 * 37.68 = 60.288 (M2) 3, (1 × 1 + 1 × 1) × 3.14 △ 4 = 1.57 (M2) 4. Maximum volume of wooden box:

The perimeter of a piece of square paper is 12 decimeters. If you cut it into the largest circle, what is the perimeter of the circle The area is ．

12 △ 4 = 3 (decimeter) 3.14 × 3 = 9.42 (decimeter) 3.14 × (3 △ 2) 2 = 3.14 × 2.25 = 7.065 (square decimeter)

The length of a rectangular paper is 20 cm and the circumference is 60 cm. Cut out the largest circle on the paper. The circumference of the circle is 60 cm Cm, the area is Square centimeter

The width of the rectangle is 60 △ 2-20 = 10 (CM), the diameter of the circle is 10 cm, the radius is 10 △ 2 = 5 (CM), the circumference of the circle is 3.14 × 10 = 31.4 (CM), the area of the circle is 3.14 × 52 = 78.5 (square cm). A: the circumference of the largest circle is 31.4 cm, and the area of the circle is 78.5 square cm

In a square with a circumference of 56 cm, cut the largest circle. How many cm is the circumference of the circle?

The side length of the square is 56 △ 4 = 14 (CM), so the circumference of the circle is 3.14 × 14 = 43.96 (CM). A: the circumference of the circle is 43.96 cm

The perimeter of a square is equal to that of a circle. It is known that the perimeter of a square is 12.56 cm. What is the diameter of the circle?

The formula is listed by equal perimeter
The circumference formula of a circle is π D
∴πd=12.56 ∵ π≈3.14
d=4 CM
So it's 4cm

Cut the biggest circle in the square. The circumference of the circle is 12.56 cm. How many cm is the square longer than the circumference of the circle
Sorry, I have the wrong number. It's 25.12cm. I'm sorry

d=c\3.14=25.12/3.14=8
So the side length of the square is 8
Perimeter = 32
Square circumference circle circumference = 32-12.56 = 6.88

It is known that the circumference of the big circle is twice that of the small circle, and the area of the small circle is 24 cm less than that of the big circle
fast

The radius of the big circle is r, and the radius of the small circle is r
2 Π r = 2 * 2 Π r shows that r = 2R
Π R * r - Π R * r = 24 by taking r = 2R in, we can get 3 Π R * r = 24 Π R * r = 8, and the area of small circle is 8

There is a board which is 1 meter long and 5 decimeters wide. How many circles can be sawed out? How many square decimeters is the area of each circle?
How many square decimeters is the rest

Is it 5 decimeters wide? If 1 meter = 10 decimeters, two circles with a diameter of 5 decimeters can be sawed theoretically
The area of each circle is S1 = π × 2.5 ^ 2 = 19.635 square decimeters;
Board area s = 10 × 5 = 50 square decimeters;
The remaining area s 2 = S-2 × s 1 = 10.73 square decimeters

If a piece of square paper with a circumference of 12 decimeters is used to cut into the largest circle, then the circumference of the circle is 12 decimeters______ Decimeter