In this paper, a 20 cm long wire is used to encircle a rectangle. The functional relationship between the area s (CM & # 178;) and the length x (CM) of the encircled rectangle is obtained, and the value range of the independent variable x is determined

s=x（10-x）=-x^2+10x
Because the aspect ratio is larger and less than 10 cm, x > 10-x and X

A 20 cm long iron wire is surrounded into a rectangle, and the relationship between the area ycm2 of the rectangle and the length xcm of one side of the rectangle is given______ ．

The length of the other side of the rectangle is 20 △ 2-x = 10-x, y = x (10-x) = - x2 + 10x

A 40cm long iron wire is used to form a plane figure. (1) if it is enclosed as a square, the side length is , with an area of In this case, the difference between length and width is (2) if it is enclosed in a rectangle with a length of 12cm, the width is , with an area of In this case, the difference between length and width is (3) if it is enclosed into a rectangle with a width of 5cm, the length is 5cm , with an area of In this case, the difference between length and width is (4) if a circle is formed, the radius of the circle is , with an area of (π is taken as 3.14, and the result is kept to one decimal place); (5) conjecture: (1) when the perimeter is constant, if the enclosed figure is a rectangle, then when the difference between the length and width is smaller and smaller, the area of the rectangle will be larger and smaller (fill in "big" or "small") and (2) in various plane figures surrounded by the same perimeter__ It's the largest area

(1) According to the meaning of the title, the length of the square is 40 △ 4 = 10cm, then the area is 10 × 10 = 100cm2, the difference between length and width is 10-10 = 0cm; (2) let the width be xcm, then 2 (12 + x) = 40, and the solution is x = 8, the area is 12 × 8 = 96cm2; the difference between length and width is 12-8 = 4cm; (3) let the length be YC

A square hole with a side length of 1cm is pulled out from two opposite sides of a cube wood with an edge length of 10cm. The surface area and volume of this figure are

The surface area increased by 8 square centimeters to 608 square centimeters
The volume has been reduced by 2 cubic centimeters to 998 cubic centimeters

In this paper, a 20 cm long wire is used to encircle a rectangle. The functional relationship between the area s (CM & # 178;) and the length x (CM) of the encircled rectangle is obtained, and the value range of the independent variable x is determined