How to draw a line into two triangles  

How to draw a line into two triangles  

I've seen this question many times. It's from the Mathematical Olympiad!
The following online search better answer!
The answer to [draw a straight line on a Pentagon and divide it into two triangles]
Answer: the first intuition of this problem is impossible! Quadrilateral can do it! Please get rid of this idea to reach the second stage of solving the problem
The second stage: This Pentagon is trapezoid, or some people insist that trapezoid in the mathematical sense is impossible, so they come up with other concave convex Pentagon - forming two extremes, without considering another result! (in fact, there are two answers to this question at the same time) at this stage, there is an answer