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The concept of mathematical perimeter in grade three
The concept of mathematical perimeter in Grade Three is introduced as follows:

The sum of all the edges of a planar geometric figure is called the perimeter of the figure.

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 (d is the diameter, R is the radius, π), and the perimeter of a sector = 2R+nπR÷ 180? (n= central angle) = 2R+kR (k= radian).

Extended data:

Correlation formula

Circle: C=πd=2πr (d is diameter, r is radius, π).

The circumference of a triangle is C = a+b+c(abc is three sides of a triangle).

Quadrilateral: C=a+b+c+d(abcd is the side length of quadrilateral)

Special: rectangle: C=2(a+b) (a length b width)

Square: C=4a(a is the side length of the square)

Polygon: C= sum of all sides.

Sector circumference: C = 2R+nπR÷ 180? (n= central angle) = 2R+kR (k= radian)

How to find the perimeter of a triangle? If I tell you that the three sides of a triangle are A, B and C, then the perimeter of the triangle is equal to A plus B plus C. If the rectangle only tells you the length and width, the length is A and the width is B, then the perimeter of the rectangle is equal to 2a plus 2b. If I tell you that one side of a square is A, then the circumference of the square is 4a. Therefore, as long as you understand the concept, it is a very simple topic to find the perimeter in grade three.