Tools: scale, long enough line, a leaf.

1, prepare a line long enough to wrap around the leaf edge, and mark the starting point and ending point of winding.

2. Draw a straight line, that is, measure the distance between the end points of the mark with a scale as the circumference of the blade.

Method 2: Trimming method.

Tools: scissors, scales, blades.

1. Cut off the edges of the leaves with scissors.

2, leveling.

Extended data

The 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 the curriculum standard about perimeter 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.

The perimeter formula of regular graphics:

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)

Rectangle: C=2(a+b) (a is long and b is wide)

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)