Basic formula: the circumference of a rectangle = (length+width) × 2 = 2 (a+b) = (a+b) × 2. Trapezoidal area = (upper bottom+lower bottom) × height ÷2s=(a+b)h÷2.

Introduction:

"Length" is often used as a geometric concept, also called length, to describe the degree of lateral extension of an object or the extension of time. The original meaning of "wide" is that the house is wide and big, and later it refers to a vast area. The word "width" also refers to the horizontal distance of an object from its original meaning. "Height" In mathematical geometry, it is often necessary to measure the height of a figure.

In mathematics, the definition of the length, width and height of a cuboid is controversial. Some people think that length is not necessarily longer than width, while others think that length is longer than width. Generally speaking, there are the following viewpoints: the front is long and the side is wide: according to the placement position, the horizontal side of the front is the length of a cuboid, the side pointing to the observer is wider, and the upper and lower sides are higher.

Length, width and short: when the cuboid is placed in a fixed position, we are used to calling the longer side in the bottom surface as long, the shorter side as wide and the side perpendicular to the bottom surface as high. Length and width: according to the placement position, the side height in the up and down direction, the two sides adjacent to the bottom surface, if one side is considered to be long, the other side is wide.