1, the algorithm of parallel four-sided row area is: the bottom times the height, which is a * H.

If it is divided into steps, it should be the origin of parallelogram area algorithm.

First, pass through a vertex of the quadrilateral line and make it high to one side.

Secondly, the extended shear translation coincides with the other side to form a rectangle.

Thirdly, the area S=a*h is obtained according to the area of the rectangle.

2、y = 3x(x≤5)

2x (x≥5)

Program box: 1. Weigh the luggage. 2. Baggage weighing more than 5 kilograms shall be charged according to 2 yuan per kilogram, and luggage weighing less than 5 kilograms shall be charged according to 3 yuan per kilogram.