1, the circumference of a rectangle = length+length+width+width.

2. The circumference of rectangle =2× length +2× width.

3. The circumference of a rectangle =2× (length+width).

Let the length of a rectangle be a, the width of a rectangle be b and the circumference of a rectangle be c, then the formula of the circumference of a rectangle is expressed in letters as C=2(a+b).

Extended data:

1, the definition of rectangle

A rectangle is a parallelogram with right angles. A square is a special rectangle with four sides of the same length.

2. Definition of length and width of rectangle

(1) According to custom, the long side of a rectangle is called long and the short side is called wide.

(2) The same direction as the horizontal plane is called length, and vice versa. The length and width of a rectangle are relative, so we can't absolutely say "longer than wider".

3. The nature of the rectangle:

The two diagonals are equal; Two diagonal lines are equally divided; Two groups of opposite sides are parallel respectively; The two groups of opposite sides are equal respectively; All four corners are right angles; There are two symmetrical axes (there are four squares); Unstable (easily deformed); The square of the diagonal length of a rectangle is the sum of the squares of both sides; The quadrilateral obtained by connecting the midpoints of the sides of the rectangle in turn is a diamond.