Only know the area of the rectangle to find the perimeter, and there is only know the perimeter of t

1.The radius of the circle = the area of the circle =

Square side length = square area =

So the area of the circle is the largest.

2.Square side length = 1225 = 35cm Square circumference = 35 * 4 = 140cm

The radius of the circle 1256 400=20cm The circumference of the circle = assuming that one side of the rectangle is 1, then the other side = 1225 1=1225 The circumference of the rectangle = (1225 + 1) * 2 = 2452 cm

So the circumference of the rectangle is the largest, and the circumference of the circle is the smallest.

If the area of these three figures is equal, then the size relationship between their perimeters is: the perimeter of the rectangle The perimeter of the square The perimeter of the circle.

1.There is a rope long, and Xiaohong, Xiaodong and Xiaolin each want to use this rope to enclose a piece of land on the playground. The area enclosed in a circle is the largest.

2.The circumference of the square is 35*4=140 meters.

The circumference of the circle is 2*20* meters.

The area of the three figures is equal and the perimeter: the circumference of the circle is less than the circumference of the square is less than the perimeter of the rectangle.

1.Round s=;

square s=;

The circumference is fixed, and the closer the side length, the larger the area. So the square area is the largest.

2. The circumference of the square is c = 35 + 35 = 70

The circumference of the circle c=2*20*;

Assuming that one side of the rectangle is 5, then the other side = 1225 5 = 205, obviously, the circumference of the rectangle is the largest and the circumference of the square is the smallest.

1: Square: Let the side length of the square be x, then 4x=, and the solution is x=, and the square of x is.

2: Rectangle: Let the length of the rectangle be x,

Use a calculator to do the math, it's very simple.

Just knowing the perimeter of the rectangle still can't find the area, you need to give the length of the rectangle or the length of the width, because.

c = 2x (a + b), c is known, then.

a+b=1/2c

Whereas, the formula for the area of a rectangle is:

s=abSo, to know a or b, then use the known perimeter c to find the length and width of the rectangle, and then calculate the area.

Let the length be x and the width be (perimeter-2x) 2, so area = length and width = x (perimeter - 2x) 2, only know that the perimeter is not able to calculate the area or length and width, that is an indefinite value, usually give the relationship between length and width. A rectangle, a mathematical term, is a parallelogram with a corner that is at a right angle called a rectangle. It is also defined as a parallelogram with all four corners at right angles, and at the same time, a square is both rectangular and diamond-shaped.

If you know the circumference of the rectangle, you must also know the side length of one of the rectangles to be able to multiply the length by the width to find the area.

The perimeter of the rectangle is known, and the length and width can be found separately and then the sum of the differences, and then the area is found separately, when the difference between the length and width is smaller, the area is the largest.

Summary. I write by hand, slowly, but in detail and seriousness! Okay, let's send a ** question.

I write by hand, slowly, but in detail and seriousness! Okay, let's send a ** question.

Formula. Classmate, I can only give you a formula for finding the maximum value.

Is there a specific question?

From what you have learned, you can know that the perimeter of the rectangle = (length + width) * 2, and the area of the rectangle = length * width. Let the length be x, the width be (perimeter-2x) 2, and the area = length and width = x (perimeter-2x) 2.

2 only know that the perimeter is not able to calculate the area or length and width, that is an indefinite value, usually to the relationship between the length and the width. For example, if the circumference of a rectangle is 20, and the length is 4 times the width (the relationship between length and width has been given to the withered mark), find the area of the rectangle.

Let the width be x, then the length is 4x, (x+4x)*2=20, and the length is x=2, and the length = 4x=4*2=8Then the area of the rectangle = 8 * 2 = 16

There is no way to find the area, you need to know the length of at least one edge.

If it's a square, you can find it.

Suppose the side length of the rectangle is a,b

Then the circumference l=2(a+b).

Area s=axb

If we only know the value of the perimeter l, then the area contains two unknowns, and its area value is infinitely many.

Example: l=6

Then when a=1, b=5, s=1x5=5

When a=2, b=4, s=2x4=8, and so on.

Divide the perimeter by 2 minus the width to equal the length, and multiply the length by the area of the wide basket.

Or divide the circumference by 2 minus the length equals the width, and multiply the length by the width of the basket area.

Just knowing the perimeter can't find the area: the farther the value of the length and the paragraph, the flatter the rectangle is, and the smaller the area; On the contrary, the smaller the difference between the values of length and width, the more bulging the rectangle, the larger the area, the maximum is the same as the length and width (the square is a special rectangle, so it is also a rectangle), and the area is (circumference 4).

Divide the perimeter by 4 to get the side length, and then multiply the side length by the side length to equal the area. According to the data you gave, the formula is obtained: 40 4 = 10 (cm) 10 * 10 = 100 (cm2).

Length + width: 40 2 = 20 cm, width 1, length 19, area: 1 19 = 19 square centimeters width 2, length 18, area: 2 18 = 36 square centimeters width 3, length 17, area:

3 17 = 51 square centimeters. Width 9, length 11, area: 9 11 = 99 square centimeters.

Knowing the area alone does not calculate the perimeter.

The area of the rectangle s=ab A represents the length of the rectangle, and b represents the width of the rectangle, and the circumference of the rectangle c=2(a+b).

Only know s, you can't find the values of a and b, and then you can't find the perimeter.

It is not enough to know only the area, you must also know one of the length and width of the "first divide the area by the length or width, and then (length and width) multiply by 2" unless it is a special rectangular square, first open the square to get the side length, and then the side length multiplied by 4 is the perimeter, the symbol is not easy to play with a mobile phone, forgive the use of the formula.

Knowing the area alone does not calculate the perimeter, and other conditions must be required.

It is not possible to determine the perimeter by knowing the area alone.

Calculate the length and width by area and find the perimeter.

The area formula for a rectangle: length, width, area.

Let the length of the rectangle be x and the width be y, then the area s=xy and y=s x

It is obtained: The circumference of the rectangle c=(x+y) 2=(x+s x) 2 =......

First of all, if the length is x and the width is y, then the area s=xy, and y=s x

Then the circumference c=(x+y) 2=(x+s x) 2 = the specific number is calculated by yourself.

Hehe, I hope my answer is helpful to you.

Knowing only the area of the rectangle does not determine the perimeter. It is also necessary to know its length or width to determine the perimeter, or to know its length-to-width ratio to determine the perimeter.

Area s length and width x, y perimeter ls=xy

Let y=s x

l=2(x+y)=2(x+s/x)

When the area of the rectangle is equal to the area of the circle is 7 square meters, the width of the rectangle is not necessarily related to the radius of the circle.

For example, when the length of the rectangle is 7 meters and the width is 1 meter, the area remains unchanged at 7 square meters, its circumference is 16 meters, and the width is 1 meter, which is different from the radius of the circle.

Another example: when the length of the rectangle is 14 meters and the width is meters, the area remains unchanged at 7 square meters, its circumference changes from 16 meters to 29 meters, and the width changes from 1 meter to meters, which has no connection with the radius of the circle.

Therefore, knowing the circumference of the rectangle is not related to finding the area of the circle.

Since r is transformed into a circle tangent 6x2 side area, it must be larger than the circle area; r is converted into a circle with a regular 6x2 polygonal area, which must be smaller than the circle area. People didn't find out"The area of the circle is equal to 7 times the 1/3 square of the diameter d"Previously, calculations were performed with the help of area and perimeter formulas that approximated, approximated, or corresponded to the area and perimeter of a regular 6x2 polygon. Therefore, there are also expressions of approximate, close or equivalent results obtained.

According to the area "softening" equal-area deformation axioms, it is found that if the area of a circle is 7a, then the area of its inscribed square is 9a, for which the area of the circle s=7(d 3) is introduced.

The area of the rectangle is equal to the area of the circle, the length of the rectangle is equal to half of the circumference of the circle, and the width of the rectangle is equal to the radius of the circle

First find the width of the rectangle, and then the area of the s circle xrxr

Ask the landlord to add details on the relationship between the rectangle with the known perimeter and the circle with the required area.