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一、问题探究由小立方块搭成的几何体,从正面看、左面看、上面看形成的三视图(主视图、左视图、俯视图),从一个角度反映了物体存在的空间形式及数量关系.图1是由完全相同的27块小立方块搭成的一个正方体,图2是它的三种视图.若知三视图(图2)(或三图缺一),用小立方块按行列填满全覆盖,则仍需3×3×3=27个.不妨图1中除对角上三个位置的小立方块有三层外,其它位置均一层,三种视图不变,小立方块却是3×3+1×6=15个;如果图1中除对角上三个位置
First, the problem of exploration Constructed from small cubes of geometry, from the front, left to see the formation of the top view of the three views (front view, left view, top view), from an angle reflects the spatial form of objects and the relationship between quantity and quantity. Figure 1 is a cube made up of exactly the same 27 small cubes, and Figure 2 is its three views. If you know the three views (Figure 2) (or three missing), use small cubes to fill in columns and columns Full coverage, you still need 3 × 3 × 3 = 27. May wish Figure 1 in addition to the diagonal position of three small cubes have three layers, the other positions are uniform, the three views unchanged, small cubes are Is 3 × 3 + 1 × 6 = 15; if in FIG. 1 except diagonally three positions