What is the process of Chinese mathematician Liu Hui deriving trapezoidal area formula

What is the process of Chinese mathematician Liu Hui deriving trapezoidal area formula

① Two identical trapezoids are put together into a parallelogram. The bottom of the parallelogram is the sum of the top and bottom of the trapezoid. The height is equal to the height of the trapezoid, and the area is twice that of the trapezoid. According to the area of the parallelogram = bottom × height, it is deduced that the area of the trapezoid = (top and bottom) × height △ 2