The concept of perimeter in primary school mathematics
Perimeter is the length of an image in a week. For example, the perimeter of a common triangle is the sum of three sides, and the perimeter of a quadrilateral is the sum of four sides. The common perimeter of a square is equal to the side length ×4, the perimeter of a rectangle is equal to 2 (length+width), and the perimeter of a circle is equal to the diameter × π.