What is the formula for calculating the perimeter?

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).

"Understanding of perimeter" is the learning content of the third grade in the first phase of compulsory education mathematics (Volume I). The learning content of "understanding of perimeter" in the curriculum standard actually includes three levels: first, let students know the concept of perimeter and experience it in real life; Secondly, let students master the method and process of measuring circumference; Finally, experience and feel the application of mathematics in life.

Extended data

The formula for calculating the perimeter of various figures is as follows:

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: =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)