三垂线定理及其逆定理揭示了平面内的直线与平面的垂线、斜线、斜线在平面内的射影这三线的垂直关系,简化了线面垂直,从而证明线与平面内直线垂直的过程大大被简化.下面举例说明如何灵活运用两定理解题. Tri-perpendicular theorem and its inverse theorem reveals the vertical relationship between the straight line in the plane and the three lines of the plane’s vertical line, diagonal line, and slash line’s projection in the plane, simplifying the vertical line plane, and verifying that the line is perpendicular to the straight line in the plane. The process is greatly simplified. Here’s an example of how to use two sets of comprehension problems.