The nature and judgment of trapezoid;
One set of quadrangles with parallel opposite sides and another set of quadrangles with non-parallel opposite sides are trapezoid, but it is difficult to judge that the other set of quadrangles with parallel and unequal opposite sides is trapezoid.
The volume calculation formula of trapezoid:
V =[s 1+S2+ radical sign (S 1 * S2)]/3 * h
Note: v: volume; S 1: upper surface area; S2: lower surface area; H: high.
The area formula of trapezoid is: "Upper bottom plus lower bottom times height divided by 2".
similar
People often use "trapezoidal structure" to describe some things, such as:
"At this stage, China's reasonable talent structure should be a trapezoidal structure with a large base and a small top. Therefore, we must vigorously develop secondary vocational education to meet the urgent needs of society for skilled talents. "
"V-shaped structure, the primary industry and the tertiary industry are at both ends, and the secondary industry is at the bottom. This industrial structure is not only different from the pyramid structure in China, that is, the ∧-shaped structure, but also different from the trapezoidal structure of some developed countries in the world. "
"As far as the simplicity and flexibility of organizational structure are concerned, Berbin, the author of Future Organizational Forms, pointed out that this kind of organization will become a simpler and more flexible' ladder structure'".
Trapezoidal common auxiliary line
1 as high (one or two, depending on the actual topic)
2 translate a waist.
3 translation diagonal
4 Stretch the waist
5 Take the midpoint of one waist and connect the two ends of the other waist.