Definition of length and width of rectangle: the one in the same direction as the horizontal plane is called length and the other is called width. (The length and width of a rectangle are relative, and it cannot be absolutely said that "it is longer than the width", but it is customary to say that the long is long and the short is wide; Sometimes because of the different positions of the graphics, they are not necessarily long. )

The rectangle has a circumference of 40, a length of y and a width of x. Traditionally, the range of width is 0.