(1) Write the definition, formula and characteristics of perimeter. As for the figure of perimeter, I can divide it into figure perimeter and physical perimeter. Figure perimeter can be divided into various learning figures: square, rectangle, triangle, pentagon, hexagon, star, heart and so on. Physical perimeter can be divided into stationery, plants, venues, utensils, decorations, kitchen utensils and so on.

(2) After roughly listing, we took out A3 paper and rearranged it with a pencil. The text about definition is placed on the left, and the classification of graphics is placed on the right. After the whole paper went public.

(3) Carefully check that all the words, lines, boxes and drawings are arranged and the edges are drawn. After all is done, we will color the drawings separately.

Definition of perimeter: The integral of the perimeter of the edge of a limited area is called 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.