(20 13? Daishan county simulation) as shown in the figure, nine small rectangles with the same shape and size are placed in the rectangular ABCD, as shown in the relevant data diagram, and the shaded

(20 13? Daishan county simulation) as shown in the figure, nine small rectangles with the same shape and size are placed in the rectangular ABCD, as shown in the relevant data diagram, and the shaded part in the figure. Let the length and width of a small rectangle be x and y,

According to the meaning of the question

x+4y=22

3y+7=x+2y，

Get a solution

x= 10

y=3，

The length and width of this small rectangle are10,3 respectively.

∴S shaded part =S quadrilateral ABCD-9×S small rectangle = 16× 22-9× 3× 10 = 82.

Brief description of the region:

abstract

Area is defined in the current primary school textbooks as follows: "The size of the curved surface or plane figure surrounded by objects is called their area.

The concept of "plane figure" in the definition is limited by "plane", which makes it less extensive and less inclusive. For example, for a country, its area is a figure with a certain size surrounded by the boundary line on the surface of the spherical object of the earth, but it is not a plane; A cylinder's side is "flat" only when it is unfolded, and its own state is curved. It can be seen that the area is a measure of the area on a plane or surface, and it is not limited to "plane graphics".

In order to avoid limitation and ambiguity, I think the area can be simply defined as "the size of an object surface or an enclosed graphic surface, which is called their area." In this way, the concept of "surface" is used to make the semantics consistent and coordinated. More importantly, defining language can truly reveal the essential attributes of things, which is more logical, because "face" is a "trace" that is "long, wide and not thick", and this trace does not have to be "flat".

Area is a measure of a flat surface.

The area of all the surfaces of a solid is called the surface area.

The area of the bottom surface of a solid object is called the bottom area.

Region: name of disease. A kind of food. Refers to people who accumulate too much pasta. The Source of Miscellaneous Diseases, the Accumulation of Obstacles and Diseases, and the Source of Addiction: "Too many areas are cold or depressed, and the chest and stomach are full. Ferula ferulae pills are suitable for malt and radish seeds. " You can also take it with radish seed wine.

unit

The unit of measurement of the area mainly includes:

Square meters-international standard units

Public construction mu-100 square meter

Ha-10000m2

Square kilometers-1100,000 square meters

Urban system:

Square city -0.25 square kilometers

Square feet-1/9 square meters

Taiwan Province system:

Taiwan Province province A-9699.38+073 square meters.

Ping -3.3058 square meters

Hong kong:

Square feet (square feet)

The size of the surface or closed figure of an object is their area.

To compare the sizes of two graphs, it is necessary to measure them in a unified area unit.

Common units of area are square centimeter, square decimeter and square meter.

(1) A square with a side length of 1 cm and an area of1cm 2.

(2) A square with a side length of 1 decimeter and an area of 1 square decimeter.

(3) A square with a side length of 1m and an area of 1m2.

Generally, hectares and square kilometers are used to measure large areas.

(1) is a square with a side length of 100 square meter and an area of 1 hectare.

(2) Square with side length 1km and area 1km2.

Calculation method

Rectangle: S=ab (rectangular area = length × width)

Square: S=a? (Square area = side length × side length)

Parallelogram: S=ab (parallelogram area = base × height)

Triangle: S=ab÷2 (triangle area = base × height ÷2)

Trapezoid: S=(a+b)×h÷2 Trapezoid area = (upper bottom+lower bottom) × height ÷2.

Circle (perfect circle): s = π r? Area of circle (perfect circle) = π× radius× radius

Circle (excircle): s = π r? -π r 2 circle (outer ring) area = pi × outer ring radius× outer ring radius -pi × inner ring radius× inner ring radius

Circle (perfect circle sector): s = π r 2× n /360 Circle (sector) area = pi× radius× radius× sector angle /360.

Cuboid surface area: S=2(ab+ac+bc) Cuboid surface area = (length× width+length× height+width× height) ×2.

Surface area of cube: s = 6a 2 (surface area of cube = side length × side length ×6)

Surface area of a circle (perfect circle): s = 4 π r 2 Surface area of a circle (perfect circle) = pi × radius× radius× 4.