Formula of perimeter and area of shape

The formula of perimeter and area of the figure: the formula of perimeter and area is C=2πr=πd,

The length integral of the edge around a finite area is called the perimeter, which is the length of a graph. The perimeter of a polygon is also equal to the sum of all sides of a graph, the perimeter of a circle =πd=2πr, and the perimeter of a sector =2R+nπR÷ 180(n= central angle) =2R+kR.

When the space occupied by an object is a two-dimensional space, the size of the space occupied is called the area of the object, which can be plane or curved. Square meter, square decimeter and square centimeter are recognized units of area, which can be expressed in letters as (m, dm, cm).

Area is a quantity indicating the degree of a two-dimensional figure or shape or plane layer in a plane. A surface region is a simulation on a two-dimensional surface of a three-dimensional object. Area can be understood as the amount of material with a given thickness, which is necessary to form a shape model.

The formula of perimeter area is:

First, the perimeter formula

1. Perimeter of rectangle = (length+width) ×2.

2. The circumference of a square = side length ×4.

3. (Key) The circumference of a circle = π× diameter = 2×π× radius.

Second, the area formula

1. Area of rectangle = length × width.

2. Area of a square = side length × side length.

3. Area of triangle = base × height ÷2.

4. The area of parallelogram = base × height.

5. Trapezoidal area = (upper bottom+lower bottom) × height ÷2.

6. Area of (key) circle = π× radius 2.

7. (Key) lateral area of the cylinder: lateral area of the cylinder is equal to the perimeter of the bottom multiplied by the height.

8. (Key) Cylinder surface area: Cylinder surface area = bottom area+side area.

Definition of area

Area can be understood as the amount of material with a given thickness, which is necessary to form a model of shape, or the amount of paint required to cover a surface with a single coating. It is a two-dimensional simulation of curve length (one-dimensional concept) or solid volume (three-dimensional concept).

There are several well-known formulas for simple shapes, such as triangle, rectangle and circle. Using these formulas, you can find the area of any polygon by dividing it into triangles. For shapes with curved boundaries, calculus is usually needed to calculate the area. In fact, the problem of determining the digital area of aircraft is the main driving force for the historical development of calculus.

Graphics refer to many spatial shapes that can be divided by contours in two-dimensional space. Graphics are a part of space and have no spatial extensibility. They are limited and recognizable shapes.

Graphics refer to vector graphics composed of external contours. That is, straight lines, circles, rectangles, curves, charts and so on drawn by computers.

A graph uses a set of instructions to describe the content of the graph, such as describing the position dimension and shape of various primitives that make up the graph. The description object can be scaled at will without distortion. On the display side, graphics use special software to convert instructions describing graphics into shapes and colors on the screen. It is suitable for describing objects with complex contours and rich colors.