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棱锥的正视图、侧视图的高是棱锥的高,而非侧面斜高,俯视图是一个多边形,各侧棱的投影在俯视图上交于一点.所以利用逆向思维可以得到将棱锥的三视图还原成几何体的简洁方法:从棱锥的俯视图入手,在图中找较多线段的交点,就是顶点的投影点,将顶点垂直拉起(想象与顶点连接的线段可伸长),高度等于正视图的高,这样就将棱锥的三视图还原成棱锥体了,用此法可以快速破解近年相关的高考题及模拟题,下面举例说明.例1(2009年宁夏海南理)一个棱锥的三视图如图1,则该棱锥的全面积(单位:cm2)为
Pyramid of the front view, the height of the side view is the height of the pyramid, rather than the side elevation, the top view is a polygon, the projection of the side of the corner in the top view of the point of intersection. So the use of reverse thinking can get three views of the pyramid restored Simple geometric method: start from the top view of the pyramid, find more intersections in the figure, is the vertex projection point, the vertex vertical pull up (imagine the vertex connected segments can be elongated), the height is equal to the height of the front view , So that the pyramid of the three views reduced to a pyramid, with this method can quickly crack the relevant college entrance examination in recent years and simulation questions, the following example: Example 1 (Ningxia, Ningxia 2009) A pyramid of the three views shown in Figure 1 , Then the full area of the pyramid (unit: cm2) is