"What a shame!" Mr. Xi'an Li looked at his daughter's homework and was worried, he thought it was a sub-question, he just couldn't solve it, the time passed 30 minutes, Mr. Li directly gave up, and his daughter was speechless.
Fifth grade thinking training: known trapezoidal ABCD, AD=AB=3cm, CD=4cm, trapezoidal area?
This problem is easy to think of using the trapezoidal area formula to solve, but the problem does not tell the bottom length of the trapezoid and the height of the trapezoid, but tells the two waist lengths, if you use the junior high school knowledge point Pythagorean theorem, this problem is beyond the outline.
Helpless to call and ask the math teacher how to solve, it turned out that the daughter copied and missed the conditions, and there is another condition for the topic is ∠B + ∠ C = 90 degrees, too careless!
![The village's New Year's flavor, the fifteenth day of the first month does not need to be decorated with flower lanterns, because they have a drier way to play. Don't talk nonsense, start the whole work. Since you come to see the social fire, this trip will definitely make you worth the trip[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)