The length integral of the edge around a finite area is called the perimeter, which is the length of a graph. The circumference is indicated by the letter C.

Perimeter and area:

If it is a triangle with the same area, the perimeter of an equilateral triangle is the shortest; If it is a quadrilateral with the same area, the perimeter of the square is the shortest; If pentagons with the same area are used, the perimeter of regular pentagons is the shortest; If you use any polygon with the same area, the circumference of a regular circle is the shortest.

Perimeter can only be used on two-dimensional figures (planes and surfaces), and three-dimensional figures (solids) such as cylinders, cones and spheres can't express their boundary size by perimeter, but by total surface area.

Total surface area = the total area of all sides of a solid.

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