问题:三个内角都是锐角的三角形叫锐角三角形.照此类推,四个内角都是锐角的四边形可以叫做锐角四边形吗?奇怪的是我们竟然无法画出所谓的“锐角四边形”.更进一步地想,五边形、六边形中可以有几个内角是锐角呢?请你画几个图,思索探究一番.你终于发现:所有的多边形竟有一个共同 Question: Three triangles with acute internal angles are called acute triangles. By analogy, can the four internal angles with acute angles be called acute quadrilaterals? The strange thing is that we can’t even draw the so-called “sharp quadrilaterals.” Think, can there be several acute angles in the pentagons and hexagons? Please draw a few pictures and think about it. You finally discovered that all the polygons have a common